IATROGENIC SYSTEMIC ALLERGIC CONTACT DERMATITIS FROM CETIRIZINE AND LEVOCETIRIZINE

Abstract

Introduction H1 antihistamines are frequently utilized in the management of dermatitis-associated pruritus; they may be overlooked and are rarely considered as an etiology for dermatitis. Case Description A 76-year-old woman with a history of allergic rhinitis and hypertension was referred for one year of pruritic, erythematous papules/plaques scattered throughout the body, worse over sun-exposed areas. Prior dermatologic evaluation and biopsy were suggestive of allergic contact dermatitis. Patch testing was positive for fragrance mix, ethylenediamine, and balsam of peru. The patient discontinued all products containing these substances without improvement. She continued to develop new lesions. There were no new medications except cetirizine and then levocetirizine, which she continued for the management of pruritus. She was treated with multiple courses of systemic and topical corticosteroids, and hydroxychloroquine, without resolution. The patient was advised to discontinue levocetirizine, avoid cetirizine, and initiate fexofenadine. At follow up at two weeks and one year later, she reported complete resolution of the rash after discontinuation of levocetirizine. Discussion Piperazine derivative antihistamines, such as hydroxyzine, cetirizine, and levocetirizine, share a similar structure with ethylenediamine, which is a common etiology of contact dermatitis. Hypersensitivity to H1 antihistamines is rare. Continued use of H1antihistamines, despite lack of improvement or worsening of symptoms, may be incorrectly interpreted as a failure of response to treatment. Development of generalized dermatitis induced by cetirizine or levocetirizine is rarely reported. This case illustrates the importance of re-evaluation in patients who fail to respond to treatment with consideration of piperazine derivative H1 antihistamines as a possible trigger. H1 antihistamines are frequently utilized in the management of dermatitis-associated pruritus; they may be overlooked and are rarely considered as an etiology for dermatitis. A 76-year-old woman with a history of allergic rhinitis and hypertension was referred for one year of pruritic, erythematous papules/plaques scattered throughout the body, worse over sun-exposed areas. Prior dermatologic evaluation and biopsy were suggestive of allergic contact dermatitis. Patch testing was positive for fragrance mix, ethylenediamine, and balsam of peru. The patient discontinued all products containing these substances without improvement. She continued to develop new lesions. There were no new medications except cetirizine and then levocetirizine, which she continued for the management of pruritus. She was treated with multiple courses of systemic and topical corticosteroids, and hydroxychloroquine, without resolution. The patient was advised to discontinue levocetirizine, avoid cetirizine, and initiate fexofenadine. At follow up at two weeks and one year later, she reported complete resolution of the rash after discontinuation of levocetirizine. Piperazine derivative antihistamines, such as hydroxyzine, cetirizine, and levocetirizine, share a similar structure with ethylenediamine, which is a common etiology of contact dermatitis. Hypersensitivity to H1 antihistamines is rare. Continued use of H1antihistamines, despite lack of improvement or worsening of symptoms, may be incorrectly interpreted as a failure of response to treatment. Development of generalized dermatitis induced by cetirizine or levocetirizine is rarely reported. This case illustrates the importance of re-evaluation in patients who fail to respond to treatment with consideration of piperazine derivative H1 antihistamines as a possible trigger.