The differential diagnosis of urticaria
Department of Medicine, Section of Dermatology and Venereology, University of Verona, Italy
Urticaria is a common disorder, and it is distinguished into acute and chronic forms. Acute urticaria is self-limiting and a cause can be identified in many patients. Chronic urticaria is a long-lasting disease, and patients are commonly investigated for an autoimmune origin and disease association. Although diagnosis of urticaria is straightforward in most patients, it may pose at time some difficulties and may require a careful differential diagnosis with a number of conditions. Urticarial syndromes comprise both cutaneous (e.g., urticarial dermatitis, drug eruptions, urticaria pigmentosa, autoimmune bullous diseases) and systemic disorders (e.g., urticarial vasculitis, hematological diseases and autoinflammatory syndromes), which may present with urticaria-like skin lesions. In contrast to urticaria, urticarial syndromes may manifest with skin lesions other than wheals such as papules, necrosis, vesicles and hemorrhages, lesions may have a bilateral and symmetrical distribution, individual lesions have a long duration, and their resolution frequently leaves marks such as hyperpigmentation or bruising. In some instances, systemic symptoms are present. Clinical-pathological correlation is essential to make the diagnosis in these cases.
Girolomoni G. 2