Clinical Conditions that Masquerade as Urticaria

Abstract

Chronic urticaria is one of the most commonly diagnosed dermatoses. Following diagnosis, correct identification and proper treatment significantly reduces disease activity, thereby improving the patient’s quality of life. However, there is an extensive differential diagnosis for chronic urticaria that, if missed, can lead to life-threatening sequelae. Many of the diseases that masquerade as urticaria are rare and often have a significant delay in diagnosis. This paper aims to fill the gap in the literature by clearly characterising the cutaneous eruptions and atypical findings in many of the most common mimickers of chronic urticaria. Conditions such as erythema marginatum seen in conjunction with hereditary angioedema, urticaria vasculitis, autoinflammatory cryopyrin-associated periodic syndromes, adult-onset Still’s disease and systemic onset juvenile arthritis, Schnitzler syndrome, erythema multiforme, and cutaneous mastocytosis will be discussed.