Immune responses of patients with tinea imbricata.

Tinea imbricata is a chronic dermatophyte infection caused by Trichophyton concentricum affecting large areas of the skin surface. Spontaneous improvement is unusual and relapse after apparently successful treatment is common. In this study in Papua New Guinea it was found that a high proportion of infected patients had immediate-type hypersensitivity (52%) or negative responses (46%) to intradermal trichophytin. The majority of patients failed to develop delayed-type hypersensitivity on skin testing or as assessed in vitro by leucocyte migration inhibition. However, 78% of patients investigated had antibody to T. concentricum. The relevance of T-lymphocyte hyporeactivity to persistence of the infection is discussed.