History
Whealing usually develops within 5-10 minutes of stroking the skin and persists for 15-30 minutes. A short refractory period after clearance of the wheal has been reported. Giant wheals can develop if deep extension of the swelling occurs. Intermediate and delayed forms of dermographism are also described. These develop more slowly and can last several hours to days.
In patients with symptomatic dermographism, the skin eruption is associated with itching, which is often most severe at night. Symptoms can be aggravated by heat (eg, from a hot bath), minor pressure (eg, from scratching, from friction with clothes, or from rubbing with towels), exercise, stress, and emotion.
Physical Examination
Itching and whealing can affect all body surfaces, but the scalp and genitalia are less frequently involved. However, dyspareunia and vulvodynia have been reported in patients with symptomatic dermographism. [9] Rarer forms of dermographism include the following:
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Red dermographism – Repeated rubbing induces small, punctate wheals that are more prominent on the trunk than on the limbs; this form is possibly associated with seborrheic dermatitis
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Follicular dermographism – Transitory, discrete, follicular, urticarial papules occur against a bright erythematous background
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Cholinergic dermographism – A large erythematous line studded with punctate wheals similar to those of cholinergic urticaria (ie, wheals smaller than those of classic urticaria and surrounded by large areas of macular erythema) is seen; purpura may be noted in severe cases; this form can be associated with cholinergic urticaria
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Delayed dermographism – Approximately 3-8 hours after the immediate dermographic response, a deep, tender, burning wheal returns to the same site and persists for up to 48 hours; this form is recalcitrant to conventional therapy and is closely related to pressure urticaria
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Cold-precipitated dermographism – One case report has been published [10]
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Exercise-induced dermographism
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Familial dermographism – One case report has been published; this form is probably inherited as an autosomal dominant trait [11]
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Dermographism or skin writing on forearm.
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Appearance of the word "Dermatographia" on a human arm 15 minutes after the letters have been traced with a blunt object on the skin. A type of urticaria or "hives", also known as dermatographic urticaria, dermatographism, or "skin writing".
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Dermographism urticaria. Courtesy of Professor Raimo Suhonen and DermNet New Zealand (http://www.dermnetnz.org/assets/Uploads/reactions/s/dermographism2.jpg).
