Ringworm is a disease of the skin, hair, and nails which is produced by numerous varieties of vegetable parasites called "fungi."
Ringworm of the scalp. - In children ringworm is seen chiefly in the scalp, and practically all the cases of ringworm of the scalp are in children. There are, generally speaking, three varieties of ringworm in this area.
The most common type, which constitutes about 95 per cent of the cases, begins at any time during and, in the absence of treatment, disappears spontaneously at the age of puberty. It is highly infectious and is seen spread among the playmates of a child who is infected with it. It is therefore advisable that any individual afflicted with it be isolated from his fellows. The teacher must recognize the disease and send the infected child home.
This type of ringworm resists treatment by ordinary means, such as ointments and other local applications. It begins as one or more patches in which the hairs appear to be nibbled off. In the beginning these areas are about one-fourth of an inch in diameter. They may gradually enlarge and fuse to such an extent as to involve practically the entire scalp. As a rule, however, the disorder is limited to from three to a dozen round patches varying in size from a half-inch to an inch and one-half in diameter. Many of the hair stumps in the involved areas have delicate whitish sheaths about them, and the patches have the appearance of having been strewn with ashes, the grayish appearance being due to fine scaling in the areas. There is usually no redness or other sign of inflammation in the patches, and ordinarily there is no itching or other subjective symptom. Permanent baldness in the affected areas does not occur in this type of ringworm.
The next most common type of ringworm of the scalp is called "kerion" and, unlike that just described, is moist. Although it is seen most commonly in children, it sometimes occurs in adults. This variety is usually contracted from playing with animals that are infected with the causative organism, most commonly dogs or cats. This variety constitutes only about 3 per cent of the cases of ringworm of the scalp. Apparently it is not so infectious as the type previously described, but the infected child should not be allowed to attend school until he is pronounced non-infectious by a physician. This type usually occurs as from one to three or four swellings varying in size from that of a hazelnut to that of a hen's egg. The swellings are somewhat tender. Not uncommonly the lymph glands of the neck are slightly enlarged. Swellings are soft and feel as though, upon puncture, pus would be evacuated, but they do not contain pus. The hairs in the area are usually broken off at various lengths, and the inflammation present pushes these hairs from their follicles in the course of a few days or weeks. From the gaping follicle mouths a colorless, syrupy fluid exudes. Any hairs in the area can be pulled out like pins from a pincushion. After a variable period time, usually several weeks, the disorder clears up spontaneously, but proper treatment hastens the disappearance of the lesions and prevents the spread of the infection to other parts of the scalp and to persons with whom the affected individual is associated. Scarring, with baldness, usually results from this type of ringworm.
A third type of ringworm of the scalp, the rarest type, occurs as black dots the size of a pinhead or smaller scattered over the scalp. Ordinarily it can be detected only by the expert eye although sometimes it is first noticed by the observant mother or attendant when she is shampooing the child's hair. It causes very little loss of hair and is responsible for no irritation. This type, like the first described, is of human origin. The black dots mentioned are usually seen even in individuals with light hair. They are produced by the growth of a single hair curled upon itself beneath a small transparent scale. No scarring results. Isolation of the infected child should be accomplished in this type of ringworm.
All the types of ringworm of the scalp described may be associated with lesions on the non-hairy skin although this is exceptional.
Ringworm of the body
Ringworm of the hands, feet, crotch, and armpits
by Clark W. Finnerud
Common Skin Diseases of Children