Contact Urticaria With Paraphenylene Diamine, Rare or Underreported?

A 45-year old woman presented with a 2-day history of intensely itchy, erythematous wheals over her scalp and around her eyes, ears, and front of the chest. She had applied hair color and immediately developed hives on the scalp, face, and chest with rhinitis and redness in the eyes. The lesions recovered within a half hour of taking a cetirizine 10-mg tablet. She gave a similar history around three times in the past 6 months. She used a different brand of hair color every time but all were associated with the same symptoms. In the first and second episodes, the itchy wheals were localized to the scalp, but in the present episode it was most severe with eye and nasal mucosal involvement and lesions spreading to involve the face, ears, and chest. There was no oozing or eczematization present. All episodes responded well to oral cetrizine.