Background: Dermographism is a normal physiological response of the skin. The term literally means writing on the skin. Firm stroking of the skin produces an initial red line (capillary dilatation), followed by an axon-reflex flare with broadening erythema (arteriolar dilatation) and the formation of a linear wheal (transudation of fluid/edema) termed the triple response of Lewis. An exaggerated response accompanied by itching to this constitutional whealing tendency is seen in approximately 2-5% of the population and is termed symptomatic dermographism. Dermographism is the most common form of physical urticaria.
Pathophysiology: The exact mechanism of dermographism remains uncertain. Trauma may release an antigen that interacts with the membrane-bound immunoglobulin E of mast cells, which release inflammatory mediators, particularly histamine, into the tissues. This causes small blood vessels to leak, allowing fluid to accumulate in the skin. Other mediators possibly involved are leukotrienes, heparin, bradykinin, kallikrein, and peptides such as substance P.
Frequency:
* Internationally: Symptomatic dermographism is the most common of the physical urticarias, affects approximately 2-5% of the population, and can occur with other forms of urticaria. Increased incidence has been reported in pregnancy (especially in second half), at the onset of menopause, in atopic children, and in patients with Behçet disease.
Mortality/Morbidity: Simple dermographism is the most common variant, and patients with this form are asymptomatic. However, other forms are associated with pruritus. Most people with dermographism are otherwise healthy. An association with thyroid disease has been described in some patients but remains controversial.
Race: No racial variance in prevalence is known.
Sex: Whether a sexual variance in prevalence occurs is unclear. None has been consistently reported, although one study on dermographism in children reported a female predominance (Martorell, 2000).
Age: Dermographism can appear in persons of any age but is more common in young adults. Peak incidence is in the second and third decades.
History: Whealing usually develops within 5 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 (hot bath), minor pressure (scratching, friction from clothes or from rubbing with towels), exercise, stress, and emotion.
Physical: 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. Rarer forms of dermographism include the following:
* 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.
* Follicular dermographism: Transitory, discrete, follicular, urticarial papules occur on a bright erythematous background.
* Cholinergic dermographism: A large erythematous line studded with punctate wheals similar to cholinergic urticaria (wheals smaller than classic urticaria and surrounded by large areas of macular erythema). Purpura has been noted in severe cases. It can be associated with cholinergic urticaria.
* 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.
* Cold precipitated dermographism: One case report has been published.
* Exercise-induced dermographism
* Familial dermographism: One case report has been published. It is probably inherited as an autosomal dominant trait.
Causes: Symptomatic dermographism is usually idiopathic. It may have an immunologic basis in some patients. Passive transfer of the dermographic response with immunoglobulin E– or immunoglobulin M–containing serum has been reported but no allergen has been identified.
* Symptomatic dermographism may be triggered by drugs (eg, penicillin), an insect bite, Helicobacter pylori infection, or an infestation (eg, scabies, Fasciola hepatica).
* Congenital symptomatic dermographism has been described as the first sign of systemic mastocytosis.
* Approximately 75% of patients with hypereosinophilic syndrome, which has multisystem involvement and high mortality, have dermographism.
* One study reported that psychic factors and a history of stressful life events seem to play a triggering role in 30% of patients (Taskapan, 2006).
H1 antihistamines are the drugs of choice. In some patients, several antihistamines or a combination of two may be required. Sedating antihistamines such as hydroxyzine can be helpful. Regular treatment may need to be continued for several months.
The addition of H2-receptor antagonists appears to result in little symptomatic benefit, although some studies have shown a further small reduction in the whealing response.
Physical urticarias are usually unresponsive to systemic corticosteroids. UV-B light therapy and oral psoralen plus UV-A light therapy have been tried; however, the improvement was short lived and was not associated with a reduction in whealing.
* Treat symptomatic dermographism until the problem is adequately controlled or resolved.
Prognosis:
* The natural history of symptomatic dermographism is unpredictable. In many patients, the condition gradually improves and clears after several years. Symptomatic dermographism appears to have the best prognosis of the chronic urticarias in terms of clearance after 5 (36%) and 10 (51%) years (van der Valk, 2002).
Patient Education:
* Reassure patients about the benign nature of the disorder, and inform them of the possible prolonged course.
* Explain the adverse effects of antihistamines.
* For excellent patient education resources, visit eMedicine's Allergy Center and Skin, Hair, and Nails Center. Also, see eMedicine's patient education article Hives and Angioedema.
* Dermographism can be distressing but is not life threatening. Warn patients undergoing treatment with antihistamines about drowsiness, especially when driving or handling machinery.
Pathophysiology: The exact mechanism of dermographism remains uncertain. Trauma may release an antigen that interacts with the membrane-bound immunoglobulin E of mast cells, which release inflammatory mediators, particularly histamine, into the tissues. This causes small blood vessels to leak, allowing fluid to accumulate in the skin. Other mediators possibly involved are leukotrienes, heparin, bradykinin, kallikrein, and peptides such as substance P.
Frequency:
* Internationally: Symptomatic dermographism is the most common of the physical urticarias, affects approximately 2-5% of the population, and can occur with other forms of urticaria. Increased incidence has been reported in pregnancy (especially in second half), at the onset of menopause, in atopic children, and in patients with Behçet disease.
Mortality/Morbidity: Simple dermographism is the most common variant, and patients with this form are asymptomatic. However, other forms are associated with pruritus. Most people with dermographism are otherwise healthy. An association with thyroid disease has been described in some patients but remains controversial.
Race: No racial variance in prevalence is known.
Sex: Whether a sexual variance in prevalence occurs is unclear. None has been consistently reported, although one study on dermographism in children reported a female predominance (Martorell, 2000).
Age: Dermographism can appear in persons of any age but is more common in young adults. Peak incidence is in the second and third decades.
History: Whealing usually develops within 5 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 (hot bath), minor pressure (scratching, friction from clothes or from rubbing with towels), exercise, stress, and emotion.
Physical: 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. Rarer forms of dermographism include the following:
* 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.
* Follicular dermographism: Transitory, discrete, follicular, urticarial papules occur on a bright erythematous background.
* Cholinergic dermographism: A large erythematous line studded with punctate wheals similar to cholinergic urticaria (wheals smaller than classic urticaria and surrounded by large areas of macular erythema). Purpura has been noted in severe cases. It can be associated with cholinergic urticaria.
* 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.
* Cold precipitated dermographism: One case report has been published.
* Exercise-induced dermographism
* Familial dermographism: One case report has been published. It is probably inherited as an autosomal dominant trait.
Causes: Symptomatic dermographism is usually idiopathic. It may have an immunologic basis in some patients. Passive transfer of the dermographic response with immunoglobulin E– or immunoglobulin M–containing serum has been reported but no allergen has been identified.
* Symptomatic dermographism may be triggered by drugs (eg, penicillin), an insect bite, Helicobacter pylori infection, or an infestation (eg, scabies, Fasciola hepatica).
* Congenital symptomatic dermographism has been described as the first sign of systemic mastocytosis.
* Approximately 75% of patients with hypereosinophilic syndrome, which has multisystem involvement and high mortality, have dermographism.
* One study reported that psychic factors and a history of stressful life events seem to play a triggering role in 30% of patients (Taskapan, 2006).
Treatment
Medical Care: Patients with simple dermographism are asymptomatic and require no therapy. Recognition of the problem, avoidance of precipitating physical stimuli, reduction of stress and anxiety are important factors in medical care. Also, scratching because of dry skin can be reduced with good skin care and emollients.H1 antihistamines are the drugs of choice. In some patients, several antihistamines or a combination of two may be required. Sedating antihistamines such as hydroxyzine can be helpful. Regular treatment may need to be continued for several months.
The addition of H2-receptor antagonists appears to result in little symptomatic benefit, although some studies have shown a further small reduction in the whealing response.
Physical urticarias are usually unresponsive to systemic corticosteroids. UV-B light therapy and oral psoralen plus UV-A light therapy have been tried; however, the improvement was short lived and was not associated with a reduction in whealing.
Follow-Up
Further Outpatient Care:* Treat symptomatic dermographism until the problem is adequately controlled or resolved.
Prognosis:
* The natural history of symptomatic dermographism is unpredictable. In many patients, the condition gradually improves and clears after several years. Symptomatic dermographism appears to have the best prognosis of the chronic urticarias in terms of clearance after 5 (36%) and 10 (51%) years (van der Valk, 2002).
Patient Education:
* Reassure patients about the benign nature of the disorder, and inform them of the possible prolonged course.
* Explain the adverse effects of antihistamines.
* For excellent patient education resources, visit eMedicine's Allergy Center and Skin, Hair, and Nails Center. Also, see eMedicine's patient education article Hives and Angioedema.
MISCELLANEOUS
Medical/Legal Pitfalls:* Dermographism can be distressing but is not life threatening. Warn patients undergoing treatment with antihistamines about drowsiness, especially when driving or handling machinery.
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