Page:Skin Diseases of Children.djvu/35

 ber of wiry, twisted, or deformed hairs are usually seen growing around or among these cicatricial patches.

Trichophytosis capitis is a disease of youth, and even when allowed to go untreated it will tend to a spontaneous cure as the patient matures. Though ringworm of the beard is very common in men, for some inexplicable reason ringworm of the scalp is never met with in adult life in either male or female. Favus, on the other hand, occurs at all ages. Developing in youth, it may persist indefinitely, although it is far more frequent in childhood than in adult life.

The cause of ringworm and favus is the presence in the epidermis and hair follicles of a micro-organism, the growth of which gives rise to more or less inflammation and the characteristic clinical appearances already described. The parasitic fungus causing ringworm is the trichophyton. Several varieties have recently been described, but it is not as yet satisfactorily proven that these varieties of the fungus are the cause of all clinical variations noted in the course of the disease. The etiological factor in favus is the achorion. This fungus does not penetrate the shaft of the hair as readily as does the trichophyton, and hence the absence in favus of the broken hairs which are so characteristic of ringworm. Children in perfect health are liable to contract either disease from some child already affected, or possibly from some pet animal. No particular condition of the skin is necessary to furnish a congenial soil for the development of the parasite, although it is true that in weak, poorly nourished children whose heads are often moist the disease is more likely to thrive and the inflammatory symptoms to be more marked. Age, however, seems to modify the character of the soil in a notable degree, and it is well to remember the clinical fact, already mentioned, that ringworm of the scalp, so common in childhood, is never seen in adult life.

In like manner ringworm of the beard, so frequently seen in middle life, is quite exceptional among old men. In the treatment of ringworm and favus a host of local applications are recommended by dermatological writers, which only proves that the majority of them are of very little value. Moreover, an admirable prescription may be written, but if the nurse or person in charge of the patient is not given full and explicit directions as to how the treatment should be carried out, the result is certain to be unsatisfactory. The local remedy employed is often of far less importance than the exact method of its use, and attention to minute details which may seem