To the Editor:
A 33-year-old woman who was otherwise healthy presented with itchy wheals that developed within 15 to 20 minutes of removing leg hair with an electric epilator. Furthermore, she reported that small hives often developed after waxing the legs with warm wax. All lesions spontaneously disappeared within 3 hours; depilatory creams and shaving did not trigger urticarial lesions. She had no history of atopy or prior episodes of spontaneous urticaria. Symptomatic dermographism also was not reported. Classic physical stimuli that could be associated with the use of an electric epilator, such as heat, vibration, and pressure, did not elicit lesions.
Physical examination showed no active lesions. Dermographism was not inducible by stroking the patient’s skin with a blunt object. She brought personal photographs that showed erythematous follicular hives measuring 1 to 3 mm in diameter located on the distal legs (Figure). In accordance with these findings, she was diagnosed with an unusual form of physical urticaria likely resulting from hair traction and was prescribed oral H1 antihistamines to be taken a few days before and after hair removal.
Urticarial papules on the leg.
Physical urticaria are characterized by the presence of reddish, edematous, and pruritic wheals developing in response to a variety of exogenous physical stimuli such as heat, cold, vibration, dermographism, and pressure. These variants are widely described; nonetheless, follicular traction urticaria has been proposed as a new form of physical urticaria elicited by traction of hair, which would cause tension on and around hair follicles on a secondary basis.1 A PubMed search of articles indexed for MEDLINE using the term traction urticaria revealed 6 other cases. In 3 cases, hives were triggered by waxing or using an electric epilator.1-3 In 1 case, urticaria was elicited by shaving with a wet straight razor,whereas the other 2 cases were induced by the removal of patch tests.4-6 Sheraz et al7 investigated the role of dermographism in erythematous reactions during patch testing and concluded that some of these reactions might be caused by traction urticaria instead of being a form of dermographism.
Özkaya and Yazganog˘lu1 proposed that follicular dermographism should be differentiated from physical urticaria. This variant of dermographism is characterized by discrete urticarial papules appearing at the location of hair follicles after having stroked the skin with a blunt object.1,8 These lesions usually disappear within 30 minutes.8 Given that none of the reported cases presented dermographism on examination tests, we agree with Özkaya and Yazganog˘lu1 that this phenomenon of traction urticaria likely is a different condition than follicular dermographism, even though intraindividual variability sometimes can be seen in dermographism skin tests.7
We present a unique form of urticaria that easily can be misdiagnosed as pseudofolliculitis, which tends to be more commonly associated with the use of electric epilators.