Differential Diagnosis
- Contact dermatitis
- Dermographism
- Strongyloidiasis
- Systemic mastocytosis
- Angioedema
Diagnosis
The patient has dermographism.
Discussion
Dermographism is the most common form of physical urticaria, and manifests as an exaggerated wheal and flare reaction of the skin, induced by pressure. Inadvertent stroking or rubbing results in the linear wheals, which usually persist for 15-30 minutes. The exact cause of dermographism is unknown, however.
Dermographism is usually asymptomatic, but some forms are associated with pruritus.
An increased incidence has been reported during pregnancy and in individuals with Behcet’s disease, thyroid disorders, infections, and atopic dermatitis. It affects approximately 2%-5% of the population and is more common in young adults.
Acknowledgment: Image courtesy of Logical Images, Inc. (www.VisualDx.com/JUCM).