[Development and significance of occupational and iatrogenic contact sensitization in nummular microbial eczema].

The pathogenesis of the epidermal and cutaneous reactions to a microbic invasion comprises many criteria for the diagnosis of a nummular microbial eczema. Detection of the focus, healing of the eczema after focal sanitation, positive reactions to bacterial antigens, decrease of Igm and IgG, and other parameters represent the cutaneous component of the disease, while the lack of epidermal sensitizations to low-molecular haptenes and the predominantly negative epicutaneous tests constitue the accentuating criteria. The results obtained in 95 patients with nummular microbic eczema show the part played by epidermal alterations in the development of occupational an iatrogenic contact sensitizations. Moreover, these alterations allow to recognize to what extent these dermatoses are due to occupational causes.