Numerous mechanisms produce urticaria but the author suspects a type I mediation in the majority of cases. We must not lose sight of the fact, however, that other reaction types can also cause urticarial wheals. Type II cytotoxic transfusion reactions can occasionally manifest as urticaria and, likewise, type III serum sickness reactions caused by many different agents have long been known to produce cutaneous lesions representing the entire spectrum from purpura to vasculitis and erythema multiforme to urticaria. The recently described syndrome of urticaria and arthralgias in necrotizing vasculitis of the skin can probably best be included under the type III reactions though the mechanism has not been clearly delineated. The urticarias, for now, are classified as follows: the immunologic forms: type I - reagin-mediated; type II - cytotoxic antibodies; type III - immune complexes and the hereditary angioneurotic edema; the pharmacologic forms; the psychologic types; and the physical urticarias: (dermographism, pressure urticaria, cholinergic urticaria, aquagenic urticaria, cold urticaria, solar urticaria and localized heat urticaria). In this consideration of the urticarias it must be kept in mind that: not all urticaria is allergic; not all allergic urticaria is type I, and the physical urticarias may have an allergic component. This guest lecture is devoted to the interests of the practicing allergist; separate tables with separate subdivisions are then presented with many of the types of allergy mentioned in the marin classification. Examples include etiologic associations in allergic urticaria; the sequence of immune reactions to insect bites; mechanically induced urticarias; thermal urticarias; and solar urticarias. The author then comes to the atopic dermatitis, of which the following features are listed: pruritus, flexural lichenification in adults, facila and extensor involvement in infancy, chronic or chronically relapsing dermatitis, immediate skin test reactivity, white dermographism, a delayed blanch response to cholinergic agents, xerosis/ichthyosis/hyperlinear palms, pityriasis alba, keratosis pilaris, facial pallor and infraorbital darkening, Dennie's infraorbital fold, elevated serum IgE, anterior subcapsular cataracts, keratoconus, a tendency toward nonspecific hand eczema and toward repeated cutaneous infections. Atopic dermatitis is called a disease which is characterized by abnormalities related to both type I and type IV hypersensitivity. The skin lesions cannot be classified under either of those reaction types, and it is impossible to gather the various bits of information into a cohesive, comprehensive pathogenic concept (70 references).
|Original language||English (US)|
|Number of pages||8|
|Journal||Annals of Allergy|
|State||Published - Dec 1 1977|
ASJC Scopus subject areas
- Immunology and Allergy