Urticaria is one of the most common dermatologic conditions seen in a clinical practice. Up to 22% of the population will experience either acute or chronic urticaria at least once in their lifetime. Broadly speaking Urticaria is defined by its duration. That lasting less than 6 weeks is acute while a longer duration is termed chronic. From an etiologic classification there is spontaneous urticaria (which is usually idiopathic), physical urticaria (such as cold-induced, heat-induced, pressure-induced, exercise-induced, etc..), and other urticarial disorders (drug induced urticaria, contact urticaria, and urticarial vasculitis). Unfortunately, the reality is that the vast majority of urticaria remains idiopathic. That is, we are idiots to the pathology of it and never find a single cause.

There is nothing more important than a thorough history and physical exam to make the diagnosis. If the wheals last longer than 24 hours we often recommend a skin biopsy to rule out a vasculitic etiology. We also test for other autoimmunities with a CBC, ESR, CRP, BUN, Cr, UA, Liver Panel and a Thyroid Panel. A formal allergy test with attention to both inhalants and ingestants should be considered.

Treatment of course involves an attempt at discovering and eliminating any etiologies such as ace inhibitors, aspirin, NSAIDS, beta blockers, alcohol or foods. Identifying and modifying any behavioral causes is also paramount. Beyond that, we mitigate things pharmacologically. Type 1 and 2 antihistamines are standard. 85% of the histamine receptors in the skin are H1 while 15% are H2. Doxepin is a tricyclic antidepressant with both H1 and H2 activity and is often a reasonable choice for patients. Adding a leukotriene inhibitor and necessary steroids is always considered. Beyond that, alternative chemotherapeutic options such as cyclosporine, methotrexate, dapsone, and sulfasalazine exist. Topical therapies have very little role and novel agents such as Xolair and Tacrolimus have some problems. Things of course are always changing and we will always keep up on what is emerging.

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