Class VIII.—Parasitic Affections

Tinea Favosa.

(Synonym: Favus.)

What is tinea favosa?

Tinea favosa, or favus, is a contagious vegetable-parasitic disease of the skin, characterized by pin-head to pea-sized, friable, umbilicated, cup-shaped yellow crusts, each usually perforated by a hair.

Upon what parts and at what age is favus observed?

It is usually met with upon the scalp, but it may occur upon any part of the integument. Occasionally the nails are invaded. It is seen at all ages, but is much more common in children.

Describe the symptoms of favus of the scalp.

The disease begins as a superficial inflammation or hyperæmic spot, more or less circumscribed, slightly scaly, and which is soon followed by the formation of yellowish points about the hair follicles, surrounding the hair shaft. These yellowish points or crusts increase in size, become usually as large as small peas, are cup-shaped, with the convex side pressing down upon the papillary layer, and the concave side raised several lines above the level of the skin; they are umbilicated, friable, sulphur-colored, and usually each cup or disc is perforated by a hair. Upon removal or detachment, the underlying surface is found to be somewhat excavated, reddened, atrophied and sometimes suppurating. As the disease progresses the crusting becomes more or less confluent, forming irregular masses of thick, yellowish, mortar-like crusts or accumulations, having a peculiar, characteristic odor—that of mice, or stale, damp straw. The hairs are involved early in the disease, become brittle, lustreless, break off and fall out. In some instances, especially near the border of the crusts, are seen pustules or suppurating points. Atrophy and more or less actual scarring are sooner or later noted.

Itching, variable as to degree, is usually present.

What is the course of favus of the scalp?

Persistent and slowly progressive.

Fig. 66.

Achorion Schönleinii X 450. (After Duhring.)
Showing simple mycelium, in various stages of development, and free spores.

What are the symptoms of favus when seated upon the general surface?

The symptoms are essentially similar to those upon the scalp, modified somewhat by the anatomical differences of the parts. The nails, when affected, become yellowish, more or less thickened, brittle and opaque (tinea favosa unguium, onychomycosis favosa).

To what is favus due?

Solely to the invasion of the cutaneous structures, especially the epidermal portion, by the vegetable parasite, the achorion Schönleinii. It is contagious. It is a somewhat rare disease in the native-born, being chiefly observed among the foreign poor. The nails are rarely affected primarily.

It is also met with in the lower animals, from which it is doubtless not infrequently communicated to man.

What are the diagnostic features of favus?

The yellow, and often cup-shaped, crusts, brittleness and loss of hair, atrophy, and the history.

Fig. 67.

Epilating Forceps.

How would you distinguish favus from eczema and ringworm?

From eczema by the condition of the affected hair, the atrophic and scar-like areas, the odor, and the history. From ringworm by the crusting and the atrophy. In this latter disease there is usually but slight scaliness, and rarely any scarring.

Finally, if necessary, a microscopic examination of the crusts may be made.

State the method of examination for fungus.

A portion of the crust is moistened with liquor potassæ and examined with a power of three to five hundred diameters. The fungus, (achorion Schönleinii), consisting of mycelium and spores, is luxuriant and is readily detected.

State the prognosis of favus..

Upon the scalp, favus is extremely chronic and rebellious to treatment, and a cure in six to twelve months may be considered satisfactory; in neglected cases permanent baldness, atrophy, and scarring sooner or later result. Although favus of the scalp persists into adult life, it becomes less active and, finally, as a rule, gradually disappears, leaving behind scarred or atrophic bald areas.

Upon the general surface it usually responds readily to treatment, excepting favus of the nails, which is always obstinate.

How is favus of the scalp treated?

Treatment is entirely local and consists in keeping the parts free from crusts, in epilation and applications of a parasiticide.

The crusts are removed by oily applications and soap-and-water washings. The hair on and around the diseased parts is to be kept closely cut, and, when practicable, depilation, or extraction of the affected hairs, is advised; this latter is, in most cases, essential to a cure. Remedial applications—the so-called parasiticides—are, as a rule, to be made twice daily. If an ointment is used, it is to be thoroughly rubbed in; if a lotion, it is to be dabbed on for several minutes and allowed to soak in.

Name the most important parasiticides.

Corrosive sublimate, one to four grains to an ounce of alcohol and water; carbolic acid, one part to three or more parts of glycerine; a ten per cent. oleate of mercury; ointments of ammoniated mercury, sulphur and tar; and sulphurous acid, pure or diluted. The following is valuable:—

℞ Sulphur, præcip., ................................ ʒij
Saponis viridis,
Ol. cadini, ....................āā................ ʒj
Adipis, .......................................... ℥ss. M.

Chrysarobin is a valuable remedy, but must be used with caution; it may be employed as an ointment, five to ten per cent. strength, as a rubber plaster, or as a paint, a drachm to an ounce of gutta-percha solution. Formalin, weakened or full strength, has been extolled. Some observers have experimentally tried the effect of x-ray exposure with alleged good results, pushing the treatment to the point of producing depilation; if used great caution should be exercised.

How is favus upon the general surface to be treated?

In the same general manner as favus of the scalp, but the remedies employed should be somewhat weaker. In favus of the nail frequent and close paring of the affected part and the application, twice daily, of one of the milder parasiticides, will eventually lead to a good result.

Is constitutional treatment of any value in favus?

It is questionable, but in debilitated subjects tonics, especially cod-liver oil, may be prescribed with the hope of aiding the external applications.

Tinea Trichophytina.

(Synonym: Ringworm.)

What is tinea trichophytina?

Tinea trichophytina, or ringworm, is a contagious, vegetable-parasitic disease due to the invasion of the cutaneous structures by the vegetable parasite, the trichophyton, or the microsporon Audouinii.

Do the clinical characters of ringworm vary according to the part affected?

Yes, often considerably; thus upon the scalp, upon the general surface, and upon the bearded region, the disease usually presents totally different appearances.

Describe the symptoms of ringworm as it occurs upon non-hairy portions of the body.

Ringworm of the general surface (tinea trichophytina corporis, tinea circinata) appears as one or more small, slightly-elevated, sharply-limited, somewhat scaly, hyperæmic spots, with, rarely, minute papules, vesico-papules, or vesicles, especially at the circumference. The patch spreads in a uniform manner peripherally, is slightly scaly, and tends to clear in the centre, assuming a ring-like appearance. When coming under observation, the patches are usually from one-half to one inch in diameter, the central portion pale or pale red, and the outer portion more or less elevated, hyperæmic and somewhat scaly. As commonly noted one, several or more patches are present. After reaching a certain size they may remain stationary, or in exceptional cases may tend to spontaneous disappearance. At times when close together, several may merge and form a large, irregular, gyrate patch.

Itching, usually slight, may or may not be present.

Exceptionally ringworm appears as a markedly inflammatory pustular circumscribed patch, formerly thought to be a distinct affection and described under the name of conglomerate pustular folliculitis. It consists of a flat carbuncular or kerion-like inflammation, somewhat elevated, and usually a dime to silver dollar in area. The most common seats are the back of the hands and the buttocks. The surface is cribriform, and a purulent secretion may be pressed out from follicular openings.

Fig. 68.

Tinea trichophytina cruris—so-called eczema marginatum—of unusually extensive development. (After Piffard.)

Describe the symptoms of ringworm when occurring about the thighs and scrotum.

In adults, more especially males, the inner portion of the upper part of the thighs and scrotum (tinea trichophytina cruris, so-called eczema marginatum) may be attacked, and here the affection, favored by heat and moisture, develops rapidly and may soon lose its ordinary clinical appearances, the inflammatory symptoms becoming especially prominent. The whole of this region may become involved, presenting all the symptoms of a true eczema; the border, however, is sharply defined, and usually one or more outlying patches of the ordinary clinical type of the disease may be seen.

Describe the symptoms of ringworm when involving the nails.

In ringworm of the nails (tinea trichophytina unguium) these structures become soft or brittle, yellowish, opaque and thickened the changes taking place mainly about the free borders. Ringworm on other parts usually coexists.

Describe the symptoms of ringworm as it occurs upon the scalp.

Ringworm of the scalp (tinea trichophytina capitis, tinea tonsurans) begins usually in the same manner as that upon the general surface, but, as a rule, much more insidiously. Sooner or later, however, the hair and follicles are invaded by the fungus, and in consequence the hair falls out or becomes brittle and breaks off. The follicles, except in long-standing cases, are slightly elevated and prominent, and the patch may have a puffed or goose-flesh appearance. In addition, there is slight scaliness.

Describe the appearances of a typical patch of ringworm of the scalp.

The patch is rounded, grayish, somewhat scaly, and slightly elevated; the follicles are somewhat prominent; there is more or less alopecia, with here and there broken, gnawed-off-looking hairs, some of which may be broken off just at the outlet of the follicles and more or less surrounded by a whitish or grayish-white dust. This type is produced by the small-spore fungus—microsporon.

Does ringworm of the scalp always present typical appearances?

Not invariably. In some cases the patch or patches may become almost completely bald, and in others a tendency to the formation of pustules, with more or less crust-formation, may be seen. The affection may also appear as small scattered spots or points.

Fig. 69.

Ringworm (rather inflammatory type, and produced by the trichophyton).

The markedly inflammatory and pustular types are produced by the large-spore fungus—trichophyton.

What is tinea kerion?

Tinea kerion (kerion) is a markedly inflammatory type of ringworm of the scalp involving the deeper tissues, appearing as a more or less bald, rounded, inflammatory, œdematous, boggy, honeycombed tumor, discharging from the follicular openings a mucoid secretion.

Does ringworm of the scalp ever occur in adults?

No. (Extremely rare exceptions.)

Fig. 70.

Ringworm Fungus (Trichophyton) x 450. (After Duhring.)
As found in epidermic scrapings of ringworm, showing mycelium and spores.

Describe the symptoms of ringworm of the bearded region.

Ringworm of the bearded region (tinea trichophytina barbæ, tinea sycosis, parasitic sycosis, barber's itch) begins usually in the same manner as ringworm on other parts, as one or more rounded, slightly scaly, hyperæmic patches. In rare instances the disease may persist as such, with very little tendency to involve the hairs and follicles; but, as a rule, the hairy structures are soon invaded, many of the hairs breaking off, and many falling out. From involvement of the follicles, more or less subcutaneous swelling ensues, the parts assuming a distinctly lumpy and nodular condition. The skin is usually considerably reddened, often having a glossy appearance, and studded with few or numerous pustules. The nodules tend, ordinarily, to break down and discharge, at one or more of the follicular openings, a glairy, glutinous, purulent material, which may dry to thick, adherent crusts.

Fig. 71.

Ringworm Fungus (Microsporon) x 500. (After Duhring.)
Short, broken-off hair of scalp invaded with masses of free spores.

The disease may be limited to one patch, or a large area, even to the extent of the whole bearded region, becomes involved. The upper lip is rarely invaded. Ringworm of the bearded region is due to the trichophyton.

Fig. 72.

Ringworm Fungus (Trichophyton) x 300. (After Duhring.)
Short, stout hair of beard, with the root-sheath attached, showing free spores and chains of spores.

To what is ringworm due?

To the presence and growth in the cutaneous structures of a vegetable parasite. Although the disease is contagious, individuals differ considerably as to susceptibility. It is much more common in children than in those past the age of puberty, ringworm of the scalp being limited to the former (rare exceptions), and tinea sycosis being a disease of the male adult.

Until recently the ringworm was thought to be due to but one fungus—the trichophyton; it is now known that there are several forms of fungi, the main forms being the small-spored (microsporon Audouini) and the large-spored (trichophyton). Of this latter there are two main subvarieties—endothrix and ectothrix. The small-spored fungus is found as the cause in the majority of scalp cases; the endothrix also commonly invades the scalp integument. The ectothrix variety is usually derived directly or indirectly from domestic animals, and is chiefly responsible for body-ringworm, and for suppurative ringworm, whether upon the bearded region or elsewhere.

What is the pathology of ringworm?

On the general surface the fungus has its seat in the epidermis, especially in the corneous layer; upon the scalp and bearded region the epidermis, hair-shaft, root and follicle are invaded. The inflammatory action may vary considerably in different cases, and at different times in the same case.

The fungus consists of mycelium and spores. In the epidermic scrapings it is never to be found in abundance, and the mycelium predominates, while in affected hairs the spores and chains of spores are almost exclusively seen, and are usually present in great profusion.

How do you examine for the fungus?

The scrapings or hair should be moistened with liquor potassæ, and examined with a power from three hundred diameters upward.

How is ringworm of the general surface to be distinguished from eczema, psoriasis and seborrhœa?

By the growth and characters of the patch, the slight scaliness, the tendency to disappear in the centre, by the history, and, if necessary, by a microscopic examination of the scales.

How is ringworm of the scalp to be distinguished from alopecia areata, favus, eczema, seborrhœa, and psoriasis?

By the peculiar clinical features of ringworm on this region—the slight scaliness, broken hair and hair stumps, with a certain amount of baldness—and in doubtful cases by a microscopical examination of the hairs.

In favus, although the same condition of the hair is noted, the yellow, cup-shaped crusts, and the presence of the atrophic areas in that disease are pathognomonic.

How is ringworm of the bearded region to be distinguished from eczema and sycosis?

By the peculiar lumpiness of the parts, the brittleness of the hair, more or less hair loss, and the history.

The superficial type of ringworm sycosis—those cases in which the disease remains a surface disease—is readily distinguished, as the symptoms are essentially the same as ringworm of non-hairy parts, except that some of the hairs in the areas may become invaded and break off or fall out.

In doubtful cases recourse may be had to microscopical examination.

What is the prognosis of ringworm of these several parts?

When upon the general surface, the disease usually responds rapidly to therapeutical applications; upon the scalp it is always a stubborn affection, and, as a rule, requires several months to a year of energetic treatment to effect a cure. In this latter region the disease will disappear spontaneously as the age of fifteen or sixteen is reached. Tinea sycosis yields in most instances in the course of several weeks or a few months.

Is ringworm of these several parts treated with the same remedies?

As a rule, yes; but the strength must be modified. The scalp will stand strong applications, as will likewise the bearded region; upon non-hairy portions the remedies should be used somewhat weaker. They should be applied twice daily; ointments, if used, being well rubbed in, and lotions thoroughly dabbed on.

How would you treat ringworm of the general surface?

By applications of the milder parasiticides, such as a ten to fifteen per cent. solution of sodium hyposulphite; carbolic acid, five to thirty grains to the ounce of water, or lard; a saturated solution of boric acid; ointments of tar, sulphur and mercury, official strength or weakened with lard; and tincture of iodine, pure or diluted.

When occurring upon the upper and inner part of the thighs (so-called eczema marginatum), the same remedies are to be employed, but usually stronger. Deserving of special mention is a lotion of corrosive sublimate, one to four grains to the ounce; or the same remedy, in the same proportion, may be used in tincture of myrrh or benzoin, and painted on the parts.

How would you treat ringworm of the scalp?

By occasional soap-and-hot-water washing; by extraction of the involved hairs, when practicable; by carbolic acid or boric acid lotions to the whole scalp, so as to limit, as much as possible, the spread of the disease; and by daily (or twice daily) applications to the patches and involved areas of a parasiticide. The following are the most valuable: the oleate of mercury, with lard or lanolin, in varying strength, from ten to twenty per cent.; carbolic acid, with one to three or more parts of glycerine or oil; corrosive sublimate, in solution in alcohol and water, one to four grains to the ounce; sulphur ointment; and citrine ointment, with one or two parts of lard. Chrysarobin is a valuable remedy, but is to be employed with care; it may be prescribed as a rubber plaster, or in a solution of gutta-percha, or as an ointment, ten to fifteen per cent. strength. β-naphthol in ointment form, five to fifteen per cent. strength, is also useful. An excellent application for beginning areas on the scalp is a solution of the red iodide of mercury in iodine tincture, one to three grains to an ounce.

A compound ointment, containing several of the active remedies named, is convenient for dispensary practice, such as:—

℞ β-naphthol, ...................................... ʒss-ʒj
Ol. cadini, ...................................... ʒj
Ungt. sulphuris, ........................ q.s. ad. ℥j. M.

In that form known as tinea kerion mild applications are demanded at first; later the same treatment as in the ordinary type.

How is ringworm of the bearded region to be treated?

On the same general plan and with the same remedies (excepting chrysarobin) as in ringworm of the scalp. Depilation is to be practised as an essential part of the treatment. Special mention may be made of an ointment of oleate of mercury, sulphur ointment, a lotion of sodium hyposulphite (ʒj-℥j), and a lotion of corrosive sublimate (gr. j-iv to ℥j). The x-ray has been used in ringworm of this region with alleged success, pushing it to the production of a mild erythema and depilation. The above methods are, however, usually successful, and are without risk of damage.

How is the certainty of an apparent cure in ringworm of the scalp or bearded region to be determined?

By the continued absence of roughness and of broken hairs and stumps, and by microscopical examination of the new-growing hairs from time to time for several weeks after discontinuance of treatment.

Cure of ringworm of the general surface is usually self-evident.

Is systemic treatment of aid in the cure of ringworm?

It is doubtful, although in children in a depraved state of health the disease is often noted to be especially stubborn, and in such cod-liver oil and similar remedies may at times prove of benefit.

Tinea Imbricata.

(Synonym: Tokelau Ringworm.)

What is tinea imbricata?

A vegetable parasitic disease of moist tropical countries, characterized by the formation of patches composed of concentrically arranged, imbricated, scaly rings. It may begin at one or several points as a brownish, slightly raised spot, spreading peripherally; the renewed epidermis of the central part of the patch goes again through the same process; the result is a small or large area of concentrically arranged, imbricated, slightly scaly eruption. Several such areas fusing together may cover a large part of the surface, the ring-like arrangement being sometimes more or less completely lost. The malady is chronic. There may be a variable degree of itching. The cause of the disease, which is of a contagious nature, is a vegetable parasite closely similar to the trichophyton. The treatment is by the parasiticides, being essentially the same, in fact, as ringworm.

Tinea Versicolor.

(Synonyms: Pityriasis Versicolor; Chromophytosis.)

What is tinea versicolor?

Tinea versicolor is a vegetable-parasitic disease of the skin, characterized by variously-sized and shaped, slightly scaly, macular patches of a yellowish-fawn color, and occurring for the most part upon the upper portion of the trunk.

Describe the symptoms of tinea versicolor.

The disease begins as one or more yellowish macular points; these, in the course of weeks or months, gradually extend, and, together with other patches that arise, may form a more or less continuous sheet of eruption. There is slight scaliness, always insignificant and furfuraceous in character, and at times, except upon close inspection, scarcely perceptible. The color of the patches is pale or brownish-yellow; in rare instances, in those of delicate skin, there may be more or less hyperæmia, and in consequence the eruption is of a reddish tinge. The number of patches varies; there may be but a few, or, on the other hand, a profusion. Slight itching, especially when the parts are warm, is usually present.

Does the eruption of tinea versicolor show predilection for any special region?

Yes; the upper part of the trunk, especially anteriorly, is the usual seat of the eruption, but in exceptional instances the neck, axillæ, the arms, the whole trunk, the genitocrural region and poplitea, and in rare cases even the lower part of the face, may become invaded.

What course does tinea versicolor pursue?

Persistent, but somewhat variable; as a rule, however, slowly progressive and lasting for years.

To what is tinea versicolor due?

To a vegetable fungus—the microsporon furfur. The affection is tolerably common, and occurs in all parts of the world. With rare exceptions, it is a disease of adults, and while looked upon as contagious, must be so to an extremely slight degree.

Fig. 73.

Microsporon Furfur x 400. (After Duhring.)
Showing mycelium in various stages of development, groups of spores and free spores.

What is the pathology?

The fungus, consisting of mycelium and spores, the latter showing a marked tendency to aggregate, invades the superficial portion of the epidermis.

Is tinea versicolor readily diagnosticated?

Yes; if the color, peculiar characters and distribution of the eruption are kept in mind.

It is not to be confounded with vitiligo, chloasma, or the macular syphiloderm. If in doubt, have recourse to the microscope.

State the method of examination for fungus.

The scrapings are taken from a patch, moistened with liquor potassæ, and examined with a power of three to five hundred diameters.

State the prognosis of tinea versicolor.

With proper management the disease is readily curable. Relapses are not uncommon.

Fig. 74.

Tinea versicolor.

What is the treatment of tinea versicolor?

It consists in daily washing with soap and hot water (and in obstinate cases with sapo viridis instead of the ordinary soap) and application of a lotion of—sulphite or hyposulphite of sodium, a drachm to the ounce; sulphurous acid, pure or diluted; carbolic acid, or resorcin, ten to twenty grains to the ounce of water and alcohol; or corrosive sublimate, one to three grains to the ounce of water. Sulphur and ammoniated-mercury ointments are also serviceable. The following used alone, simply as a soap, or in conjunction with a lotion, is often of special value:—

℞ Sulphur, præcip., ................................ ʒiv
Saponis viridis, ................................. ʒxii. M.

After the disease is apparently cured, an occasional remedial application should be made for several months, in order to guard against the possibility of a relapse.

Erythrasma.

Erythrasma.

Describe erythrasma.

Erythrasma is an extremely rare disease, due to the presence and growth in the epidermic structures of the vegetable parasite—the microsporon minutissimum. It is characterized by small and large, slightly furfuraceous, reddish-yellow or reddish-brown patches, occurring usually on warm and moist parts, such as the axillary, inguinal, anal and genitocrural regions. It is slowly progressive and persistent, but is without disturbing symptoms other than occasional slight itching.

Fig. 75.

Microsporon Minutissimum x 1000. (After Riehl.)

Treatment, which is rapidly effective, is the same as that employed in tinea versicolor.

Dhobie Itch.

Dhobie itch is a name used in certain tropical countries to designate a somewhat peculiar itching eruption of the genitocrural and axillary regions, and by some also a similar eruption about the feet. It consists of a dermatitis of variable degree, usually with a festooned, irregular border, with considerable itching. It is believed that such cases are variously due to the trichophyton of ringworm, to the microsporon furfur of tinea versicolor, to the microsporon minutissimus of erythrasma, and to other parasites.

Actinomycosis.

Describe actinomycosis.

Actinomycosis of the skin is an affection due to the ray fungus, and characterized by a sluggish, red, nodular, or lumpy infiltration, usually with a tendency to break down and form sinuses. The affection may involve almost any part, but its most common site is about the jaw, neck, and face. As a rule, the first evidence is a hard subcutaneous swelling or infiltration, which may increase slightly or considerably. The overlying skin gradually becomes of a sluggish or dark-red color. Softening ensues, and the diseased area breaks down at one or more points, from which there oozes a discharge of a sero-purulent, purulent, or sanguinolent character. In this discharge can be usually noted minute, friable, yellowish or yellowish-gray bodies representing conglomerate collections of the causative fungus.

The course of the malady is commonly slow and insidious. Unless systemic pyemic infection occurs or the fungus elements find their way to the deeper organs or structures the general health remains apparently undisturbed.

What is the treatment?

The administration of moderate to large doses of potassium iodide, conjointly with curetting or excision of the diseased mass. Local applications of iodine solution can also be tried.

Blastomycetic Dermatitis.

What do you understand by blastomycetic dermatitis?

Blastomycetic dermatitis is a rare disease beginning usually as a small papule or nodule, enlarging slowly, breaking down and developing into a verrucous or papillomatous-looking area, similar in appearance

to tuberculosis cutis verrucosa. A muco-purulent or purulent secretion can visually be pressed out from between the papillomatous elevations. It may also present the appearance of a serpiginous lupus vulgaris or syphiloderm. As a rule it is slow in its course. Furuncular or abscess-like formations may develop, usually from secondary infection. The disease is due to the invasion of the cutaneous tissues by the blastomyces.

Treatment consists in administration of moderate to large doses of potassium iodide, and in the employment of antiseptic and parasiticide applications; usually, however, radical treatment, such as employed in lupus vulgaris, may be necessary.

Scabies.

(Synonym: The Itch.)

What is scabies?

Scabies, or itch, is a contagious animal-parasitic disease characterized by a multiform eruption of a somewhat peculiar distribution, attended by intense itching.

Describe the symptoms of scabies.

The penetration and presence of the parasites within the cutaneous structures besides often giving rise to several or more complete or imperfectly formed burrows, excite varying degrees of irritation, and in consequence the formation of vesicles, papules and pustules, accompanied with more or less intense itching. Secondarily, crusting, and at times a mild or severe grade of dermatitis, may be brought about. The parasite seeks preferably tender and protected situations, as between the fingers, on the wrists, especially the flexor surface, in the folds of the axilla, on the abdomen, about the anal fissure, about the genitalia, and in females also about the nipples, and hence the eruption is most abundant about these regions. The inside of the thighs and the feet are also attacked, as, indeed, may be almost every portion of the body. The scalp and face are not involved; exceptionally, however, these parts are invaded in infants and young children.

Is the grade of cutaneous irritation the same in all cases of scabies?

No; in those of great cutaneous irritability, especially in children, the skin being more tender, the type of the eruption is usually much more inflammatory. In those predisposed a true eczema may arise, and then, in addition to the characteristic lesions of scabies, eczematous symptoms are superadded; in long-persistent cases, indeed, the burrows and other consequent lesions may be more or less completely masked by the eczematous inflammation, and the true nature of the disease be greatly obscured.

What do you mean by burrows?

Burrows, or cuniculi, are tortuous, straight or zigzag, dotted, slightly elevated, dark-gray or blackish thread-like linear formations, varying in length from an eighth to a half an inch.

Fig. 76.

Burrow, or cuniculus, greatly magnified. (After Kaposi.)

Showing the mite, ova, empty shells and excrement.

How is a burrow formed?

By the impregnated female parasite, which penetrates the epidermis obliquely to the rete, depositing as it goes along ten or fifteen ova, forming a minute passage or burrow.

Upon what parts are burrows most commonly to be found?

In the interdigital spaces, on the flexor surface of the wrists, about the mammæ in the female, and on the shaft of the penis in the male.

Are burrows usually present in numbers?

No. Several may be found in a single case, but they are rarely numerous, as the irritation caused by the penetration of the parasites leads either to violent scratching and their destruction, or gives rise to the formation of vesicles and pustules, and consequently their formation is prevented.

What course does scabies pursue?

Chronic and progressive, showing no tendency to spontaneous disappearance.

To what is scabies due?

To the invasion of the cutaneous structures by an animal parasite, the sarcoptes scabiei (acarus scabiei). The male mite is never found in the skin and apparently takes no direct part in the production of the symptoms.

Fig. 77. FIG. 78.

Sarcoptes scabiei x 100. (After Duhring.)

Female. Ventral surface. Male.

The disease is contagious to a marked degree, and is most commonly contracted by sleeping with those affected, or by occupying a bed in which an affected person has slept. It occurs, for obvious reasons, usually among the poor, although it is now quite frequently met with among the better classes.

State the diagnostic features of scabies.

The burrows, the peculiar distribution and the multiformity of the eruption, the progressive development, and usually a history of contagion.

How do vesicular and pustular eczema differ from scabies?

Eczema is usually limited in extent, or irregularly distributed, is distinctly patchy, with often the formation of large diffused areas; it is variable in its clinical behavior, better and worse from time to time, and differs, moreover, in the absence of burrows and of a history of contagion.

How does pediculosis corporis differ from scabies?

In the distribution of the eruption. The pediculi live in the clothing and go to the skin solely for nourishment, and hence the eruption in that condition is upon covered parts, especially those parts with which the clothing lies closely in contact, as around the neck, across the upper part of the back, about the waist and down the outside of the thighs; the hands are free.

State the prognosis of scabies.

It is favorable. The disease is readily cured, and, as soon as the parasites and their ova are destroyed, the itching and the secondary symptoms, as a rule, rapidly disappear.

How is scabies treated?

Treatment is entirely external, and consists of a preliminary soap-and-hot-water bath, an application, twice daily for three days, of a remedy destructive to the parasites and ova, and finally another bath.

Inquiry as to others of the family should be made, and, if affected, treated at the same time. The wearing apparel should be looked after—boiled, baked, or sulphur-fumigated.

What remedial applications are employed in scabies?

Sulphur, balsam of Peru, styrax, and β-naphthol, singly or severally combined. In children, or in those of sensitive skin, the following:—

℞ Sulphur. præcip., ................................ ʒiv
Balsam. Peruv., .................................. ʒij
Adipis,
Petrolati, .....................āā................ ℥iss. M.

And in adults, or those of non-irritable skin:—

℞ Sulphur, præcip., ................................ ℥j
Balsam. Peruv., .................................. ℥ss
β-Naphthol, ...................................... ʒij
Adipis,
Petrolati, ..............āā......... q.s. ad. .... ℥iv. M.

Styrax is a remedy of value and is commonly employed as an ointment in the strength of one part to two or three parts of lard.

Is one such course of treatment sufficient to bring about a cure?

Yes, in ordinary cases, if the applications have been carefully and thoroughly made; exceptionally, however, some parasites and ova escape destruction, and consequently itching will again begin to show itself at the end of a week or ten days, and a repetition of the treatment become necessary.

Does the secondary dermatitis which is always present in severe cases require treatment?

Only when it is unusually persistent or severe; in such cases the various soothing applications, lotions or ointments employed in acute eczema are to be prescribed.

Is a dermatitis due to too active and prolonged treatment ever mistaken for persistence of the scabies?

Yes.

Pediculosis.

(Synonyms: Phtheiriasis; Lousiness.)

Define pediculosis.

Pediculosis is a term applied to that condition of local or general cutaneous irritation due to the presence of the animal parasite, the pediculus, or louse.

Name the several varieties met with.

Three varieties are presented, named according to the parts involved, pediculosis capitis, pediculosis corporis, and pediculosis pubis; the parasite in each being a distinct species of pediculus.

Pediculosis Capitis.

Describe the symptoms of pediculosis capitis.

Pediculosis capitis (pediculosis capillitii), due to the presence of the pediculus capitis, occurs much more frequently in children than in adults. It is characterized by marked itching, and the formation of various inflammatory lesions, such as papules, pustules and excoriations— resulting from the irritation produced by the parasites and from the scratching to which the intense pruritus gives rise. In fact, an eczematous eruption of the pustular type soon results, attended with more or less crust formation. In consequence of the cutaneous irritation the neighboring lymphatic glands may become inflamed and swollen, and in rare cases suppurate. The occipital region is the part which is usually most profusely infested, more especially in young girls and women. In those of delicate skin, especially in children, scattered papules, vesico-papules, pustules, and excoriations may often be seen upon the forehead and neck. In some instances, however, especially in boys, there may be many pediculi present, with but little cutaneous disturbance, the itching being the sole symptom.

Fig. 79.

Pediculus Capitis x 25. (After Duhring.)

Female. Dorsal surface.

In addition to the pediculi, which, as a rule, may be readily found, their ova, or nits, are always to be seen upon the shaft of the hairs, quite firmly attached.

Describe the appearance of the ova.

They are dirty-white or grayish looking, minute, pear-shaped bodies, visible to the naked eye, and fastened upon the shaft of the hairs with the small end toward the root.

Is there any difficulty in the diagnosis of pediculosis capitis?

No. The diagnosis is readily made, as the pediculi are usually to be found without difficulty, and even when they exist in small numbers and are not readily discovered, the presence of the ova will indicate the nature of the affection.

Pustular eruptions upon the scalp, especially posteriorly, should always arouse a suspicion of pediculosis. The possibility of the pediculosis being secondary to eczema must not be forgotten.

What is the treatment of pediculosis capitis?

Treatment consists in the application of some remedy destructive to the pediculi and their ova. Crude petroleum is effective, one or two thorough applications over night being usually sufficient; in order to lessen its inflammability, and also to mask its somewhat disagreeable odor, it may be mixed with an equal part of olive oil and a small quantity of balsam of Peru added.

Tincture of cocculus indicus, pure or diluted, may also be applied with good results.

When the parts are markedly eczematous, an ointment of ammoniated mercury or β-naphthol, thirty to sixty grains to the ounce may be used.

Daily shampooing with soap and water, and the twice daily application of a five per cent. carbolic acid lotion, together with the use of a fine-toothed comb, is a safe and efficient method for dispensary practice; as it is, indeed, for any class of patients.

How are the ova or their shells to be removed from the hair?

By the frequent use of acid or alkaline lotions, such as dilute acetic acid and vinegar, or solutions of sodium carbonate and borax.

Pediculosis Corporis.

Describe the symptoms of pediculosis corporis.

Pediculosis corporis is dependent upon the presence of the pediculus corporis (pediculus vestimenti), a larger variety than that infesting the scalp. It is characterized by more or less general itching, together with various inflammatory lesions and excoriations. As the parasites are to be found chiefly in the folds and seams of the clothing, visiting the skin for the purpose of feeding, the various symptoms—the minute hemorrhagic puncta showing the points at which they have been sucking, and the consequent papules, pustules and excoriations—are, therefore, to be found most abundantly on those parts with which the clothing comes closely in contact, as, for instance, around the neck, across the shoulders, around the waist, and down the outside of the thighs. It is uncommon in children.

Fig. 81.

Pediculus Corporis x 25. (After Duhring.)

Female. Dorsal surface.

State the diagnostic characters of pediculosis corporis.

The presence of the minute hemorrhagic puncta, the multiform character and peculiar distribution of the eruption. Careful search will almost invariably disclose one or more pediculi.

What is the treatment of pediculosis corporis?

The clothing and bed-coverings are to be thoroughly baked or boiled, the pediculi and their ova being in this manner destroyed; a thymol or carbolized boric-acid lotion may be used to relieve the cutaneous irritation.

When attention to the wearing apparel is not immediately practicable, ointments of sulphur and staphisagria, and lotions of carbolic acid, may be advised as temporary measures. The wearing of a bag of loosely woven texture containing some lump sulphur next to the skin is useful in such cases; at the temperature of the body the sulphur undergoes slow oxidation. In hairy individuals the malady is often persistent, due to the fact that ova have become attached to the hair and a new progeny soon hatched out. Continued treatment over a few weeks will usually suffice to rid the patient of their presence.

Pediculosis Pubis.

Describe the symptoms of pediculosis pubis.

Pediculosis pubis is a condition due to the presence of the pediculus pubis, or crab-louse. It is characterized by more or less itching about the genitalia, together with papules, excoriations, and other inflammatory lesions. The amount of irritation varies; it may be slight, or, on the other hand, severe. The parasite, which is the smallest of the three varieties, may be discovered upon close examination seated near the roots of the hairs, clutching the hair, with its head downward and buried in the follicle. The ova may be seen attached to the hair-shafts.

It infests adults chiefly, being in many instances probably contracted through sexual intercourse.

Is the pediculus pubis found upon any other part of the body?

Yes. Although its favorite habitat is the region of the pubes, it may, in exceptional instances, also infest the axillæ, the sternal region of the male, the beard, eyebrows, and even the eyelashes.

State the diagnostic characters of pediculosis pubis.

The region involved, itching, variable amount of irritation, and, above all, the presence of the pediculi and their ova.

Fig. 82.

Pediculus Pubis x 25. (After Duhring.) Female. Dorsal surface.

Name several applications prescribed for pediculosis pubis.

A lotion of corrosive sublimate, one to four grains to the ounce; infusion of tobacco; a ten to twenty per cent. ointment of oleate of mercury; ammoniated mercury ointment, and a five to ten per cent. β-naphthol ointment. Repeated washings with vinegar or dilute acetic acid, or with alkaline lotions, will free the hairs of the ova.

Cysticercus Cellulosæ.

Describe the cutaneous disturbance produced by the cysticercus cellulosæ.

The presence of cysticerci in the skin and subcutaneous tissue gives rise to pea to hazelnut-sized, rounded, firm, movable tumors which, when developed, may remain unchanged for months. The parasites are disclosed by microscopic examination.

Most of the cases have been observed in Germany.

Filaria Medinensis.

(Synonym: Guinea-worm.)

State the character of the lesions produced by the filaria medinensis.

The young microscopic worm penetrates the skin or deeper tissue, where it grows gradually, finally reaching several inches or more in length and about a half-line in thickness; inflammation is excited and a tumor-like swelling makes its appearance, which, sooner or later, breaks, disclosing the worm. It may also present a cord-like appearance. It is rarely met with outside of tropical countries.

Treatment consists in gradual extraction, or in the injection of a corrosive sublimate solution (1:1000) into the forming tumor. Asafetida internally has been found to be curative, the parasite being destroyed and subsequently absorbed or discharged.

Ixodes.

(Synonym: Wood-tick.)

State the character of the cutaneous disturbance produced by the ixodes.

The tick sticks its proboscis into the skin and sucks blood until it is several times its natural size, and then falls off; an urticarial lesion results. If caught in the act the animal should not be forcibly extracted, as its proboscis may be thus broken off and remain in the skin, and give rise to pain and inflammation. It may be made to relinquish its hold by placing on it a drop of an essential oil.

A thymol or carbolized boric-acid lotion will relieve the irritation.

Leptus.

(Synonym: Harvest-mite.)

State the characters of the lesion produced by the leptus.

This minute brick-red mite buries itself in the skin, especially about the ankles and feet, giving rise to papules, vesicles and pustules.

Treatment consists of the use of a mild sulphur ointment or of a carbolic-acid lotion.

Œstrus.

(Synonym: Gad, or Bot-fly.)

Describe the cutaneous disturbance produced by the œstrus.

The ova are deposited in the skin, develop and give rise to the formation of furuncle-like tumors with central aperture, through which a sanious discharge exudes; or as the result of the burrowing of the larvæ, irregular serpiginous lines or wheals are produced.

It is chiefly met with in Central and South America.

Larva migrant, or creeping disease, is doubtless in this same class. It is characterized by a thread-like linear formation of an erythematous, erythemato-papular, or vesicular nature that gradually extends, the older part disappearing; considerable surface may be covered before the parasite disappears or dies. The treatment consists in endeavoring to destroy the organism by means of excision or caustic applications at the point of its suspected site which is just ahead of the extending line.

Pulex Penetrans.

(Synonyms: Sand Flea; Jigger.)

Describe the cutaneous disturbance produced by the pulex penetrans.

This microscopic animal penetrates the skin, especially about the toes, producing an inflammatory swelling, vesicle or pustule, or even ulceration. It is met with in warm and tropical countries.

Treatment consists in extraction. Essential oils are used as a preventive. A carbolic-acid or alkaline lotion relieves irritation.

Cimex Lectularius.

(Synonym: Bed-bug.)

Describe the characters of a bed-bug bite.

An inflammatory papule or wheal-like lesion results, somewhat hemorrhagic; the purpuric or hemorrhagic point or spot remains after the swelling subsides, but finally, in the course of several days or a few weeks, disappears.

Treatment consists in the application of alkaline or acid lotions.

Culex.

(Synonym: Gnat; Mosquito.)

Describe the cutaneous disturbance produced by the culex.

It consists of an erythematous spot or a wheal-like lesion.

Alkaline or acid lotions usually give relief.

Pulex Irritans.

(Synonym: Common Flea.)

Describe the cutaneous disturbance produced by the pulex irritans.

It consists of an erythematous spot with a minute central hemorrhagic point. In irritable skin, a wheal-like lesion may result.

Treatment consists of applications of camphor or ammonia-water; carbolic acid and thymol lotions are also useful.

RELATIVE FREQUENCY OF THE VARIOUS DISEASES OF SKIN AS SHOWN BY THE STATISTICS (123,746 CASES) OF THE AMERICAN DERMATOLOGICAL ASSOCIATION FOR TEN YEARS, 1878-87.

CLASSIFICATION OF
DISEASES. No.
Cases. %
Cases. CLASSIFICATION OF
DISEASES. No.
Cases. %
Cases.

Class I. Disorders of the
Glands. Verruca necrogenica 2 .001

1. OF THE SWEAT GLANDS. Nævus pigmentosus 88 .064

Hyperidrosis 328 .265 Xerosis 100 .080

Sudamen 268 .216 Ichthyosis 309 .249

Anidrosis 11 .009 Onychauxis 70 .056

Bromidrosis 112 .090 Hypertdichosis 515 .416

Chromidrosis 7 .005 3. OF CONNECTIVE TISSUE.

Uridrosis .... .... Sclerema neonatorum .... ....

2. OF THE SEBACEOUS
GLANDS 238 .193 Scleroderma 38 0.030

Seborrhœa: 1812 1.47 Morphœa 39 0.031

a. oleosa 367 .296 Elephantiasis 57 0.046

b. sicca 395 .319 Rosacea: 785 0.634

Comedo 1225 .989 a. erythematosa 381 0.308

Cyst 6 .004 b. hypertrophica 58 0.047

a. Milium 225 .183 Frambœsia 22 0.018

b. Steatoma 151 .122 Class V. Atrophies.

Asteatosis 8 .006 1. OF PIGMENT.

Class II. Inflammations. Leucoderma 77 0.062

Exanthemata 1770 1.43 Albinismus 9 0.008

Erythema simplex 1064 .859 Vitiligo 191 0.155

Erythema multiforme: 915 .730 Canities 43 0.035

a. papulosum 325 .262 2. OF HAIR.

b. bullosum 37 .029 Alopecia 926 0.749

c. nodosum 82 .066 Alopecia furfuracea 830 0.67

Urticaria 2994 2.47 Alopecia areata 794 0.641

pigmentosa 1 .0008 Atrophia pilorum propria 23 0.019

Dermatitis: 1720 1.39 Trichorexis nodosa 3 0.002

a. traumatica 468 .378 3. OF NAIL 26 0.021

b. venenata 616 .498 Atrophia unguis 19 0.015

c. calorica 224 .187 4. OF CUTIS 6 0.005

d. medicamentosa 108 .087 Atrophia senilis 15 0.013

e. gangrænosa 8 .006 Atrophia maculosa et
striata 23 0.019

Erysipelas 1026 .829 Class VI. New Growths.

Furunculus 2129 1.72 1. OF CONNECTIVE TISSUE. 1 0.0008

Anthrax 252 .203 Keloid 152 0.124

Phlegmona diffusa 265 .215 Cicatrix 89 0.065

Pustula maligna 197 .159 Fibroma 93 0.075

Herpes simplex 2057 1.66 Neuroma 11 0.009

Herpes zoster 1428 1.15 Xanthoma 69 0.056

Dermatitis herpetiformis 41 .033 2. OF MUSCULAR TISSUE.

Psoriasis 4131 3.34 Myoma 1 0.0008

Pityriasis maculuta et
circinata 71 .057 3. OF VESSELS.

Dermatitis exfoliativa 16 .012 Angioma 462 0.373

Pityriasis rubra 44 .032 Angioma pigmentosum
et atrophicum 13 0.010

Lichen: 144 .116 Angioma cavernosum 22 0.018

a. planus 154 .124 Lymphangioma 16 .012

b. ruber 27 .021 4. Mycosis fongoide 1 .0008

Eczema: 37661 30.43 Rhinoscleroma 3 .002

a. erythematosum .... .... Lupus erythematosus 477 .385

b. papulosum .... .... Lupus vulgaris 536 .433

c. vesiculosum .... .... Scrofuloderma 663 .536

d. madidans .... .... Syphiloderma: 13888 11.22

e. pustulosum .... .... a. erythematosum .... ....

f. rubrum .... .... b. papulosum .... ....

g. squamosum .... .... c. pustulosum .... ....

Prurigo 34 .027 d. tuberculosum .... ....

Acne 9077 7.34 e. gummatosum .... ....

Acne rosacea 398 .321 Lepra: 24 .020

Sycosis 227 .185 a. tuberosa 7 .005

Impetigo 1769 1.43 b. maculosa 4 .003

Impetigo contagiosa 600 .485 c. anæsthetica 6 .004

Impetigo herpetiformis 10 .009 Carcinoma 1068 .863

Ecthyma 726 .587 Sarcoma 55 .044

Pemphigus 183 .148 Class VII. Neuroses.

Ulcers 3021 2.44 Hyperæsthesia: 4 .003

Class III. Hemorrhages. a. Pruritus 2716 2.12

Purpura: 341 .275 b. Dermatalgia 11 .009

a. simplex 181 .145 Anæsthesia 22 .018

b. hæmorrhagica 49 .039 Class VIII. Parasitic
Affections.

Class IV. Hypertrophies. 1. VEGETABLE.

1. OF PIGMENT. Tinea favosa 354 .286

Lentigo 127 .103 Tinea trichophytina: 2289 1.85

Chloasma 560 .452 a. circinata 705 .569

2. OF EPIDERMAL AND
PAPILLARY LAYERS. b. tonsurans 675 .545

Keratosis: 94 .076 c. sycosis 365 .295

a. pilaris 103 .083 Tinea versicolor 1263 1.02

b. senilis 68 .055 2. ANIMAL.

Molluscum epitheliale 172 .139 Scabies 3192 2.58

Callositas 110 .090 Pediculosis capillitii 2579 2.09

Clavus 84 .068 Pediculosis corporis 1704 1.38

Cornu cutaneum 42 .034 Pediculosis pubis 436 .352

Verruca 1252 1.09 Total 123746