Treatment of Acute Urticaria (Hives)
–R/o anaphylaxis. Epinephrine IM is urgently indicated for laryngeal swelling and respiratory symptoms. This should be done first, before anything else.
–H1-antihistamines (1st-line tx). 2nd Generation H1 antihistamines are preferred to 1st generation (Diphenhydramine and Hydroxyzine) b/c they last longer and have less s/e like drowsiness.
–H2 + H1 blockers. H2-blockers are modestly helpful as adjuncts to H1 blockers.The combination of an H1 antihistamine and an H2 antihistamine may be more effective for acute urticaria than an H1 antihistamine alone, even though the data is weak. H2 antihistamine blockers e.g. Ranitidine 50mg and Diphenhydramine 50mg combined worked better in one research than Diphenhydramine 50mg and placebo.
–Steroids: A brief course (ie, usually a week or less) of systemic glucocorticoids may be added to antihistamine therapy to control persistent and severe symptoms. Glucocorticoids do not inhibit mast cell degranulation but probably act by suppressing a variety of contributing inflammatory mechanisms.
Give oral glucocorticoids, in addition to H1 and H2 antihistamines, to patients whose initial symptoms are severe and to those with prominent angioedema. A course of glucocorticoids may also be added later for urticaria that is persistent despite antihistamines.
In adults, Prednisone 30 to 60 mg daily, with tapering of the dose over five to seven days. In children, Prednisolone 0.5 to 1 mg/kg/day (maximum 60 mg daily), with tapering of the dose over five to seven days
Continue the antihistamine therapy during and after the course of steroids because some patients experience an exacerbation as the glucocorticoids are tapered or discontinued. If symptoms do not recur over several days after stopping glucocorticoids, then antihistamines can be discontinued also.
*Leukotriene receptor antagonist may be added if H1 blockers are not enough..
Background
Acute = Present for less than six week
Urticaria is also called welts or wheals
References
Am Fam Physician. 2017 Jun 1;95(11):717-724. http://www.aafp.org/afp/2013/0501/p626.html
Am Fam Physician. 2011 May 1;83(9):1078-1084. http://www.aafp.org/afp/2011/0501/p1078.html