Current opinion in allergy and clinical immunology
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Antihistamines exert pharmacologic effects by binding to four histamine receptors (H1-H4) at different affinities, producing variable effects depending on the receptor they predominantly bind to. This review's purpose is to determine the relative potency of antihistamines by comparing their binding affinities to these receptors. Studies on binding affinities of antihistamines to histamine receptors were reviewed and the dissociation constant for inhibitor binding (Ki) analyzed to determine the most and least potent antihistamine for each receptor. ⋯ This review summarizes the relative potency of antihistamines based on their binding affinities to the four histamine receptors. Although data on binding affinities of antihistamines to the H4 receptor are sparse, it is apparent that further research on these histamine subtypes may open new venues for more direct treatment with a higher therapeutic efficacy on allergic disorders including those affecting the ocular surface.
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Both atopy and diseases from the spectrum of dermatitis and eczema are among the most frequent clinical problems worldwide; nevertheless, they are still poorly defined and too frequently misdiagnosed. In the present review, studies pertinent to this topic were systematized and critically assessed with particular attention to definitions of relevant diseases. ⋯ The interplay between atopy and diseases from the spectrum of dermatitis and eczema is not fully understood; nevertheless, their coexistence and overlapping are not rare. Therefore, every patient with eczema - regardless of age, sex or atopic status - should undergo an extensive diagnostic programme including each atopic eczema, irritant contact dermatitis, allergic contact dermatitis, and protein contact dermatitis. Better definitions and well designed studies are necessary to achieve detailed information on the complex relationships between each atopy, atopic eczema, and the three contact dermatitides.