Dermatitis cruris pustulosa et atrophicans.

Dermatitis cruris pustulosa et atrophicans (DCPA) is a distinctive type of chronic superficial folliculitis, primarily affecting the lower limbs. It is characterized by symmetrical follicular pustules of both legs, with cutaneous edema, resulting in alopecia, atrophy and scarring. It was first described by Clarke, from West Nigeria, in 1952 and well illustrated in his book "Skin diseases in the African," under the initial label of "Nigerian shin disease." Subsequently, it was described in India as well, in 1964, and continues to be a problem in dermatology clinics across the country. It is predominantly a disease of men and has a high prevalence in some geographical regions; up to 3-4% in Madras, South India. Some unique features that distinguish DCPA from banal pustular folliculitis include its peculiar localization to the legs, extreme chronicity, resistance to therapy and inevitable alopecia and atrophy of the involved skin, with little postinflammatory hyper- or hypopigmentation. Further, even in the presence of extensive lesions, there are no systemic features. Coagulase-positive Staphylococcus aureus is known to have a role in the etiology of DCPA, but the exact etiopathogenesis still needs to be elucidated. Immunological postulates such as hypergammaglobulinemia have been put forward to explain the chronicity of the condition. A number of therapeutic agents have been tried in various studies, including cotrimoxazole, psoralen with ultraviolet A (PUVA) therapy, ciprofloxacin, pentoxifylline, rifampicin, dapsone, minocycline and mupirocin (topical) with variable success rates. Although a well-recognized entity in dermatology clinics in tropical countries, DCPA has received little attention in the dermatological literature and has only a few studies to its credit. Its unique clinical picture, unclear etiopathogenesis and resistance to therapy afford a vast scope for further investigation and study.