Additional testing can be done if presentation suggests underlying disease or specific causes requiring confirmation.
A complete blood count with differential and measurement of erythrocyte sedimentation rate or C-reactive protein level are recommended to rule out systemic disease.
These include cutaneous mastocytosis (urticaria pigmentosa), urticarial vasculitis, cryoglobulinemia, and several rare disorders.
These conditions may be distinguished based on differences in presentation.
Rarely, it may represent serious systemic disease or a life-threatening allergic reaction.
Treatment includes avoidance of triggers, although these can be identified in only 10 to 20 percent of patients with chronic urticaria.Urticaria involves intensely pruritic, raised wheals, with or without edema of the deeper cutis.It is usually a self-limited, benign reaction, but can be chronic.Various sources recommend urinalysis, measurement of thyroid-stimulating hormone level, and liver function testing to look for other causes.A = consistent, good-quality patient-oriented evidence; B = inconsistent or limited-quality patient-oriented evidence; C = consensus, disease-oriented evidence, usual practice, expert opinion, or case series.