Asian Journal of Case Reports in Medicine and Health

Introduction: The immune system can cause excessive immunological and inflammatory responses, leading to hypersensitivity reactions such as angioneurotic edema and urticaria. Angioneurotic edema presents as sudden, recurrent swelling of cutaneous and mucosal tissues (e.g., lips, eyes, and throat) while urticaria manifests as itchy welts. Type I hypersensitivity reactions causing both and urticaria are rare.

Case Summary: A 58-year-old female patient presented with facial puffiness for one day and itching for three days. She had a history of thalassemia minor, hypothyroidism, and type 2 diabetes mellitus. Laboratory results showed Hb 8.2 g/dl, TLC 14,760 cells/mm³, and platelets 7.89 lakh/mm³. She was diagnosed with angioneurotic edema with urticarial rash. Medication history revealed intake of doxycycline 100 mg twice daily for 2.5 days (5 doses) before symptoms began, promoting discontinuation of the drug. Treatment with pheniramine 50 mg thrice daily led to resolution of symptoms. The patient was labeled as allergic to doxycycline and discharged with an alert card. She is currently asymptomatic.

Causality and Severity Assessment: The Naranjo and WHO probability scales indicated a “probable” relationship between doxycycline and the reaction. Severity, assessed using the modified Hartwig and Siegel Scale, was “moderate (level 4b)”.

Conclusion: This case highlights a rare but clinically significant type-1 hypersensitivity reaction to doxycycline, presenting with urticaria. The strong time temporal relationship and symptom resolution after withdrawal confirm causality. Proper documentation and patient education are essential to prevent future drug exposure.