1. Are some antihistamines better than others for pruritus?
Possibly; evidence is conflicting, but several studies have shown that older systemic antihistamines that cause greater somnolence are actually more effective at alleviating pruritus than newer, longer-acting antihistamines (e.g. astemizole, loratadine, terfenadine, cetirizine).
2. Do topical antihistamines alleviate pruritus?
Not usually, except for widespread pruritus seen with insect bites and urticaria. Use of topical antihistamines for pruritus or rash that is widespread should be discouraged, because toxicity may result from systemic absorption.
3.Does scratching make the pruritus better or worse?
Worse; scratching leads to the release of the mediators of inflammation including histamine that, in turn, leads to more pruritus thus creating a vicious cycle.
4. Are there any useful adjuncts to reduce pruritus?
Yes, keeping skin moist with moisturizers and avoiding dry environments. Avoid overwashing, especially with hot water and/or alkaline soaps.
(Modified from 5-Minute Pediatric Consult book)