Urticaria is a common dermatologic sign of a variety of diseases seen in primary care settings. It can affect skin on any part of the body and is primarily mediated by histamine release from mast cells. Urticaria, with or without angioedema, is classified as acute or chronic. Acute urticaria, defined as lasting less than 6 weeks, is self-limited. Diagnostic testing is typically not required for acute urticaria; limited investigation is recommended for chronic urticaria. H1 antihistamines are the initial pharmacologic agent used to provide relief from symptoms of acute urticaria. Second-generation H1 antihistamines are preferred over first-generation because of fewer sedating effects. Short courses of oral corticosteroids may be used if there is minimal or no response to antihistamines. First-line treatment of chronic urticaria should follow a stepped plan that includes second-generation H1 antihistamines, increasing the dose up to four times if needed. Recommendations for the use of H2 blockers and leukotriene receptor antagonists are conflicting; however, if there is minimal or no response to a second-generation antihistamine, leukotriene receptor antagonists or other immunosuppressants are recommended. [corrected] Long-term corticosteroids are not recommended for chronic urticaria. Omalizumab is approved by the US Food and Drug Administration for the treatment of refractory chronic urticaria. Due to their safety profile, second-generation H1 antihistamines should be used in pregnant and breastfeeding individuals, children, and older adults.
Urticaria is a common dermatologic symptom of a variety of diseases seen in primary care settings. Urticaria typically presents as pruritic, well-circumscribed, erythematous, and edematous plaques with an initial central pallor, often called wheals or hives, that measure several millimeters to several centimeters and last for less than 24 hours (Figure 1). In skin of color, erythema and pallor may be less obvious (Figure 2). Wheals are caused by increased blood flow, vasodilation of blood vessels, and vascular permeability to the dermis due to mast cell activation, which releases histamine and other inflammatory mediators.
SORT: KEY RECOMMENDATIONS FOR PRACTICE
| Clinical recommendation | Evidence rating | Comments |
|---|---|---|
| For acute urticaria, diagnostic testing is typically not required.12,17 | C | Consensus, usual practice, and disease-oriented evidence |
| When evaluating for an underlying cause of chronic urticaria, diagnostic testing includes differential blood cell count; ESR; and CRP, total IgE, TSH (thyrotropin), and IgG antithyroid peroxidase levels. Further testing for other biomarkers, often in consultation with specialty care, may be needed.14 | C | Consensus, usual practice, and disease-oriented evidence |
| Second-generation H1 antihistamines are preferred over first-generation H1 antihistamines for acute and chronic urticaria because of fewer sedating effects.17 | C | Expert opinion and consensus guidelines |
| Omalizumab (Xolair) can be used in patients with antihistamine-resistant chronic urticaria.23 | C | Expert consensus guidelines and FDA-approved therapy |
| Long-term oral corticosteroids are not recommended for treatment of chronic urticaria.17 | A | Consistent evidence from randomized controlled trials |
CRP = C-reactive protein; ESR = erythrocyte sedimentation rate; FDA = US Food and Drug Administration; Ig = immunoglobulin; TSH = thyroid-stimulating hormone.
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. For information about the SORT evidence rating system, go to https://www.aafp.org/afpsort.
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