Generalized allergic contact dermatitis from nitroglycerin in a transdermal therapeutic system.

A 62-year-old woman developed pruritus, oedema, erythema and vesiculation, well demarcated at the application sites of nitroglycerin TTS on the trunk and upper arms (Fig. 1). Lesions healed with post-inflammatory hyperpigmentation. Two weeks before, the patient had started treatment for coronary insufficiency with daily nitroglycerin transdermal patches (Dermatrans 5®, Recordati group, Madrid, Spain), and 6 days later she noted pruritus. The symptoms started 12 h after rechallenge. Although the patches were substituted with another brand, the pruritus and eczema did not decrease. Nitroglycerin TTS was withdrawn and the patient was treated with topical corticosteroids and oral antihistamines for a week. Later, patch tests were carried out with adhesives and nitroglycerin 1%, 0.5% and 0.1% in petrolatum (Fig. 2). All the nitroglycerin patch tests were positive at 48 h (stronger) and at 72 h, but the adhesive proved negative. The woman subsequently received sublingual nitroglycerin without adverse effects. Furthermore, the patient had been on isosorbide mononitrate orally for the last year because she had high blood pressure, but no cross-sensitivity allergic reaction occurred.