Differential Diagnosis of Chronic Spontaneous Urticaria

Patients with chronic recurrent wheals most commonly receive the diagnosis of chronic spontaneous urticaria, although a number of autoimmune, autoinflammatory, and malignant diseases can be suspected based on certain red flags. These warning signs are a wheal duration of more than 24 hours, post-inflammatory hyperpigmentation, and systemic symptoms such as arthralgia and fever and/or elevated inflammatory markers. Here, we detail the case of an adult patient who initially received the diagnosis of chronic spontaneous urticaria, discussing possible differential diagnoses and outlining options for treating the patient once a diagnosis has been established. We highlight the need for a careful examination of laboratory and histologic findings and other investigations, including serum immunofixation electrophoresis and genetic testing.