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.
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.
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.