Familial dermographism

Alternate names

Dermo-distortive urticaria; Familial dermatographism; Dermographism; Dermatographia

Definition

Familial dermographism is a condition also known as skin writing. When people who have dermatographia lightly scratch their skin, the scratches redden into a raised wheal similar to hives.

File:Dermographism back.jpg

File:Dermographism.jpg

Epidemiology

• Dermatographism is the most common type of urticaria, frequently presenting in young adults with the peak incidence in the second and third decades.
• One study of pediatric patients showed a female predominance.
• One report cited a case of familial dermatographism.

Cause

• The exact cause of dermatographism is unknown.
• However, the release of histamine from mast cells is thought to play a role.
• Dermatographism has been seen in people with diabetes, hyperthyroid, hypothyroid, menopause, pregnancy, or medication-related.

Types

There are several rare subtypes of dermatographism:[1].

• Red dermatographism (small punctate wheals, predominantly on the trunk)
• Follicular dermatographism (isolated urticarial papules)
• Cholinergic dermatographism (similar to cholinergic urticaria – large erythematous line marked by punctate wheals)
• Delayed dermatographism (tender urticarial lesion reappears 3 to 8 hours after the initial injury that persist up to 48 hours)
• Cold-precipitated
• Exercise-induced
• Familial

Signs and symptoms

• Signs and symptoms of dermatographia include raised red lines, swelling, inflammation, hive-like welts and itching.
• Symptoms usually disappear within 30 minutes.

Diagnosis

This condition is diagnosed by a health care provider writing or drawing on the patient's skin with a tongue depressor or other implement, to see whether a red wheal appears soon afterwards.

Treatment

• Prevention and avoidance of precipitating factors such as physical stimuli and decreasing stressors are important factors in controlling dermatographism. Most patients are asymptomatic, and therapy should be restricted to symptomatic patients.
• Choice therapy includes treatment with H1 antihistamines such as cetirizine or loratadine.
• H2 antihistamines can be combined for more complete therapy if H1 blockers are insufficient to control the pruritus.
• Hydroxyzine, a sedating antihistamine, is a valid option and can be taken before sleep.
• Omalizumab is under construction in research trials focusing on treating dermatographism with 72% efficacy on 150 mg and 58% efficacy on 300 mg.
• Light therapy has shown some efficacy in treating dermatographism, yet most patients relapse within 2 to 3 months of completing therapy.
• Adjunctive treatment with over the counter vitamin C 1000 mg daily is thought to help degrade histamine and increase removal, diminishing the triple response of Lewis.[2].

Prognosis

• Dermatographism is a benign condition.
• In a minority of cases, pruritus can accompany the condition.
• Compared to the other chronic urticarias, symptomatic dermatographism displays the most expedited clearance of the condition after 5 years (36%) and 10 years (51%).

NIH genetic and rare disease info

• NIH info on Familial dermographism

Familial dermographism is a rare disease.