[The allergic skin].

The main cutaneous manifestation of allergy is eczema. In atopic dermatitis, the epidermal Langerhans cells express receptors for IgE and the eczematous lesions may be associated with other atopic disorders such as asthma or pollinosis. In contact dermatitis, the epidermal Langerhans' cells play the role of antigen-presenting cells; the antigens eliciting the eczematous lesions may be of occupational, vestimentary, cosmetical, therapeutical or other environmental origin. Epicutaneous test procedures enable their identification. Paraptic eczema is a concept including all the cutaneous and systemic complications of contact dermatitis.