(Lichen Simplex Circumscriptus)

By circumscribed neurodermatitis is meant one or several irregularly shaped, usually small, and much thick­ened itchy patches which have be come lichenified; they look like the skin of a rhinoceros. There is a sharply denned separation between the patch and the healthy skin. Cir­cumscribed neurodermatitis is usually seen on the neck or on the hands, arms, or legs. It does not occur in babies, and is not common in chil­dren. The causation is obscure. It is seen in allergic or nonallergic per­sons. It is thought to be caused by primary itching, followed by long-continued rubbing and scratching. Although it is thought by some to be of allergic origin, this has not been proved, and the removal of foods or other allergens from the diet does no good. The best treatment is the persistent use of a strong tar ointment with the addition of salicylic acid, well rubbed in.

Fig.   19. Circumscribed neurodermatitis     (lichen    simplex    circumscriptus). mann’s Practice of Pediatrics.)