CONSECUTIVE cases of dermatitis, chiefly or exclusively affecting the hands, 388 in number, seen in private practice, have been studied and classified etiologically as examples of dermatitis due to: (1) external physical or chemical agents acting as a primary irritant or allergen, with or without secondary infection; (2) primary external infection with virus, bacterium, fungus or other parasite; (3) internal chemical disorder induced by ingested or injected medication, nutritional or endocrine derangement or ingested food allergen; (4) systemic or focal infection, including pustular bacterid; (5) distant dermatitis elsewhere on the body, such as tinea pedis or varicose ulcer, with secondary manifestations on the hands, and (6) specific disease of unknown causation, such as psoriasis, lichen planus, nummular dermatitis, seborrheic dermatitis, keratoderma climacterium or Darier's dyskeratosis. Other varieties of dermatitis of the hands include (7) malformation, such as epidermolysis bullosa, and (8) neoplasm, such as senile keratoses or hemangiosarcoma of Kaposi;