Acquired Palmoplantar Keratoderma

Shaily Patel, Matthew Zirwas, Joseph C. English

Palmoplantar keratodermas (PPKs) are a diverse entity of disorders that are characterized by abnormal thickening of the skin on the palms and soles. Traditionally they have been classified as either hereditary or acquired and are distinguished from each other on the basis of mode of inheritance, presence of transgrediens (defined as contiguous extension of hyperkeratosis beyond the palmar and/or plantar skin), co-morbidities with other symptoms, and extent of epidermal involvement, namely diffuse, focal, and punctate. As the terms hyperkeratosis and keratoderma have been used interchangeably throughout the literature, we define acquired keratoderma as a non-hereditary, non-frictional hyperkeratosis of the palms and/or soles that involves >/=50% of the surface of involved acral areas and that may or may not be associated with clinical and histologic inflammation. Given the numerous possible underlying causes for acquired PPKs, evaluation of patients presenting with acquired PPK can be a perplexing task. To facilitate such evaluations, this review categorizes the acquired PPKs as: keratoderma climactericum, drug related, malnutrition associated, chemically induced, systemic disease related, malignancy associated, dermatoses related, infectious, and idiopathic. In order to avoid the possibility of overlooking an underlying etiology and to eliminate excessive testing, we present an algorithm for assessing patients presenting with acquired PPK. The first step should include a comprehensive history and a physical examination, including a complete skin examination. If findings are consistent with a hereditary keratoderma, then a genetics consultation should be considered. Any findings suggestive of underlying conditions should be aggressively evaluated and treated. If no pertinent findings are identified after a history and a physical examination, laboratory and radiology studies should be undertaken in a systematic, logical fashion. In terms of treatment, the most successful results occur when the underlying etiology is diagnosed and treated. If no such etiology is evident, then conservative treatment options include topical keratolytics (urea, salicylic acid, lactic acid), repeated physical debridement, topical retinoids, topical psoralen plus UVA, and topical corticosteroids. Etretinate and acitretin have also shown some success as alternative treatments in recalcitrant cases.