Dermatographic Urticaria

Print

Overview

Dermatographism is a physical urticarial state characterized by whealing after stroking or scratching the skin. It frequently occurs for some period after an episode of acute urticaria. Most patients are mildly dermatographic and usually require no therapy. Some patients have severe pruritus and whealing and are said to have "symptomatic dermatographism" or "dermatographic urticaria." Treatment of such individuals is warranted. Because skin lesions and symptoms result from activation of skin mast cells and release of mast cell contents, the therapeutic strategy is to prevent mast cell activation and/or inhibit the action of released mast cell mediators (primarily histamine).

First steps

Therapy is usually limited to the use of antihistamines alone or in combination. The therapeutic goal is to control pruritus and to limit whealing as much as possible. Patients may tolerate cutaneous lesions if symptoms are controlled. For any antihistamine prescribed, first determine the dose necessary to control pruritus and administer the medication in a manner that allows 24-hour coverage. The following agents are preferred as initial therapy:

1. A nonsedating antihistamine, loratidine 10mg once daily, fexofenadine 60mg twice daily (or 180 mg once daily), or cetirizine 10mg once daily are efficacious and do not cause drowsiness in most patients.
2. Hydroxyzine 25-75 mg nightly or up to 50 mg four times daily is often effective, but may cause drowsiness if daytime doses are given.

Subsequent steps

After symptoms have been controlled for 2 weeks, determine the least amount of medication necessary to meet the patient's therapeutic needs. Attempt to wean the patient from medication every 2-3 months.

Alternative steps

1. Sinequan 25-75 mg nightly can be effective when other antihistamines fail.
2. Cimetidine, an H₂ antagonist, 400 mg four times daily in combination
   with an H₁ blocker is specifically useful in symptomatic dermatographism and should be considered when the simple antihistamine regimens listed above are ineffective.

Pitfalls

1. The prescription of systemic steroids should be avoided. Although these agents can be effective, partial control of this benign process is preferable to the complications of chronic systemic steroid therapy.
2. Dermatographism is rarely the presenting manifestation of systemic mastocytosis.
3. In patients who do not respond to the regimens listed above, urticarial lesions may be caused by an underlying disorder such as vasculitis. In these cases, a skin biopsy may be necessary to establish the diagnosis.

CONTENT PROVIDED BY:

Disclaimer: The material above has been prepared by Derm101.com. It has not been reviewed by the DermQuest Editorial Board for its accuracy or reliability. Reference to any products, service, or other information does not constitute or imply endorsement, sponsorship, or recommendation by members of the Editorial Board.