Symptomatic Dermatographism Misattributed to Cockroach Exposure: A Diagnostic Pitfall.

Allergen exposure can present with a broad clinical spectrum. Individuals exposed to allergens may develop respiratory diseases such as asthma, skin manifestations such as urticaria, and potentially anaphylaxis. For those who reside in urban or unsanitary environments, cockroaches can serve as an unfortunate and persistent exposure to such allergens. Cockroach allergens are classically associated with IgE-mediated respiratory diseases. However, reliance on exposure history alone may lead to diagnostic misattribution when cutaneous symptoms occur without systemic allergic features. We describe a 22-year-old woman from Philadelphia who presented with a 48-hour history of diffuse pruritus and widespread erythematous linear and maculopapular wheals involving the arms, legs, trunk, and face following significant household cockroach exposure. Physical examination demonstrated inducible wheals consistent with symptomatic dermatographism, without evidence of systemic allergic reaction or arthropod envenomation. The temporal association with environmental exposure initially suggested an allergic etiology; however, clinical findings supported a diagnosis of physical urticaria rather than a true allergen-mediated process. Treatment with loratadine 10 mg once daily resulted in symptomatic improvement. This case highlights how dermatographism may be incorrectly attributed to environmental allergens in the setting of coincidental exposure and the importance of careful clinical evaluation to avoid unnecessary allergy-directed testing, particularly in urban settings with high pest prevalence.