Thirty-one immunocompromised patients (22 renal allograft recipients, 5 patients receiving chronic corticosteroid therapy, and 4 patients undergoing chemotherapy for acute leukemia) with significant dermatologic infection, excluding typical cellulitis and herpesvirus infections, were retrospectively identified over a 12-year period. Of these 31 patients, 15 (48%) had infection restricted to their skin, 6 (19%) appeared to have primary cutaneous infection that spread hematogenously to other parts of the body, 2 (6%) had infections of adjoining nasal tissue that spread to contiguous skin, and 8 (26%) appeared to have disseminated systemic infection that spread to the skin. In six of the eight patients with apparent secondary skin involvement, the development of the cutaneous lesion was the first clinical indication of disseminated infection. Eleven immunocompromised patients (35%) with bacterial infection of the skin or subcutaneous tissue were identified. These patients could be divided into three categories: leukemic patients with bacteremic gram-negative infection metastasizing to the skin (3 cases), renal transplant recipients with recurrent staphylococcal infection on and around the elbow ("transplant elbow") or streptococcal sepsis from a site of cellulitis (5 cases), and immunocompromised patients with opportunistic bacterial infection due to Nocardia asteroides or atypical mycobacteria (3 cases). Seventeen immunocompromised patients (55%) with fungal infection of the skin or subcutaneous tissue were identified. These included 12 patients with opportunistic fungal infection (Cryptococcus neoformans, 4 cases; Aspergillus species, 3 cases; Paecilomyces, 2 cases; Rhizopus species, 2 cases; and Candida tropicalis, 1 case) and 5 patients with extensive, confluent cutaneous dermatophyte infections. One patient with protothecosis and two patients with extensive papillomavirus infection were identified. Of these latter two cases, one had his immunosuppression discontinued, with clearing of his extensive warts; the other had confluent warts of the face and neck that subsequently underwent malignant degeneration to squamous cell carcinoma while chronic immunosuppressive therapy was continued.(ABSTRACT TRUNCATED AT 400 WORDS)