Family and personal histories of atopy, total IgE level in serum, AB0 blood groups, trichophytin reactions, IgE RAST, IgG RAST and precipitating antibodies were investigated in patients with hereditary palmo-plantar keratoderma and dermatophytosis. 44% of the patients with dermatophytosis had a personal and/or family history of atopy and 67% a total IgE greater than 100 kU/ml. No significant differences in the rate of dermatophytosis were found between atopics and non-atopics, nor were there differences between patients with a total IgE above and those with a level below 100 kU/ml. The determination of AB0 blood groups showed that T. mentagrophytes occurred significantly more often in patients with blood group A. All delayed trichophytin reactions were negative. A positive immediate trichophytin reaction was found in only 1 patient, who also had a raised level of IgE antibodies against dermatophytes. The level of specific IgG antibodies was increased in patients infected with T. rubrum and E. floccosum, which two species were found to have at least one antigen in common. Homologous precipitating antibodies occurred in 54% of the patients with hereditary palmo-plantar keratoderma, which is a considerably higher value than that reported in dermatophyte infected patients without this inherited disorder.
