Allergy is an acquired specific alteration in the capacity of the system to react, brought about by an antibody mechanism. Conventionally Antibodies are modified serum globulins that make it possible for certain serologic and/or cellular reactions to develop; the term "antibody" is extended to include a cell with specifically altered properties toward the antigen. In primary allergic dermatoses the cutaneous lesions develop as a direct consequence of the antigen-antibody union; erythema nodosum and other "id" reactions are of this type. In nonprimary allergic dermatoses there is some less direct relationship to the allergic process; most cases of atopic dermatitis are of this type. Nonprimary allergic sensitivity, like the primary types, can be either immediate or delayed. H'story taking and skin testing are extremely valuable and often essential for the etiological diagnosis; but they never establish the morphologic diagnosis, which is the physician's first responsibility. Skin tests are sometimes worse than useless because so many atopic persons give numerous positive reactions that are etiologically irrelevant. There are no cutaneous tests that help to establish the diagnosis of infectious eczematoid dermatitis and nummular eczema, but the morphologic characteristics of these two dermatoses are fairly precise, so that these labels can be applied on the basis of inspection alone. The distinction between primary and nonprimary allergic dermatoses is of practical importance because it determines how the condition will respond to any interference with the antibody-antigen union.
Rostenberg A. THE ALLERGIC DERMATOSES. JAMA. 1957;165(9):1118–1125. doi:10.1001/jama.1957.02980270028007
Customize your JAMA Network experience by selecting one or more topics from the list below.
Create a personal account or sign in to: