From the Guidelines
Chronic physical urticaria, specifically dermographism, is a condition characterized by the appearance of raised, red welts in response to physical stimuli, such as firm stroking or scratching of the skin, and is classified as a type of physical urticaria that can be reproducibly induced by the same physical stimulus 1.
Key Characteristics
- The condition is triggered by mechanical stimuli, resulting in the release of histamine and other inflammatory chemicals from mast cells in the skin 1.
- The welts typically appear within minutes of skin pressure and may be itchy or painful, usually resolving within 30 minutes to a few hours 1.
- Dermographism is a type of physical urticaria that is distinct from other forms, such as delayed pressure urticaria, vibratory angio-oedema, and thermal urticarias 1.
Treatment and Management
- Treatment primarily involves antihistamines, with second-generation options like cetirizine (10mg daily), loratadine (10mg daily), or fexofenadine (180mg daily) being first-line choices due to their minimal sedating effects 1.
- For more severe cases, higher antihistamine doses or combinations may be needed, and some patients benefit from adding H2 blockers like ranitidine.
- Avoiding tight clothing, harsh soaps, and extreme temperatures can help reduce flare-ups.
- Most patients experience significant improvement with consistent antihistamine use, though the condition may persist for years or even decades.
- If standard treatments fail, dermatology referral may be necessary for consideration of immunomodulatory medications like omalizumab or cyclosporine in severe cases.
Important Considerations
- The duration of individual weals can be helpful in distinguishing between different clinical patterns, with weals in physical urticaria typically lasting less than an hour 1.
- Angio-oedema without weals should be distinguished from angio-oedema occurring with weals, as it may be caused by angiotensin-converting enzyme (ACE) inhibitors or be a presentation of C1 esterase inhibitor (C1 inh) deficiency 1.
From the Research
Definition and Characteristics of Chronic Physical Urticaria (Dermographism)
- Chronic physical urticaria, also known as dermographism, is a common subtype of chronic urticaria that manifests as a linear wheal after scratching or friction, with or without angioedema 2.
- The condition is characterized by intensely pruritic wheals, sometimes with edema of the subcutaneous or interstitial tissue, and is caused by immunoglobulin E- and non-immunoglobulin E-mediated release of histamine and other inflammatory mediators from mast cells and basophils 3.
- Dermographism is present in a large number of healthy individuals and is due to a combination of pressure and shearing forces 4.
Diagnosis and Evaluation
- The gold standard for diagnosis is a medical history and provocation test or dermatographic test 2.
- The Urticaria Control Test (UCT), Chronic Urticaria Quality of Life questionnaire (CU-Q2oL), and Dermatology Life Quality Index (DLQI) are also effective tools for evaluating disease control in dermographism patients 2.
- Diagnosis is made clinically, and anaphylaxis must be ruled out 3.
Treatment and Management
- The mainstay of treatment is avoidance of triggers, if identified 3.
- Nonsedating H1 antihistamines are the first-line medications recommended for dermographism, and the dosage can be increased up to 4 times for those who do not respond to standard doses 2.
- Cetirizine, a second-generation antihistamine, has been shown to be effective in reducing symptoms and wealing in dermographic urticaria 5, 6.
- Omalizumab can be considered for off-label use in refractory cases, and other drugs with potential therapeutic effects are still being explored 2.