Narrowband ultraviolet B phototherapy is beneficial in antihistamine-resistant symptomatic dermographism: a pilot study.

Background: Symptomatic dermographism is the most common type of physical urticaria. It can be severe and poorly controlled with H1 antihistamines in some patients. Photochemotherapy (psoralen plus ultraviolet [UV] A) may help the itch of dermographism but the effect of narrowband (NB) UVB therapy has not been previously studied.

Objectives: We sought to examine the clinical efficacy of NB UVB therapy for itch and whealing in symptomatic dermographism and to assess the duration of the effect during 3 months of follow-up.

Methods: Eight patients (6 female) were enrolled into an open uncontrolled prospective study. Intensity of itching and whealing was assessed with visual analog scales and the whealing response was evaluated by testing with a dermographometer at pressures of 20, 36, and 60 g/mm2 on the upper aspect of the back. NB UVB phototherapy was given for 6 weeks 3 times weekly starting at 50% of minimal erythema dose with 20% to 0% increments as tolerated. Fexofenadine (180 mg/d) was taken during the run-in period and subsequently throughout the study and follow-up as required. Patients were followed for 3 months with regular assessments every 6 weeks after completion of phototherapy.

Results: All patients showed an improvement in itching at the end of NB UVB treatment (mean [SD] reduction 52.3% [31.6%]). Subjective assessment of whealing revealed a significant improvement in all but two patients (mean [SD] reduction 71% [54%]). There was a small and statistically significant improvement in cumulative dermographometer-induced wheal widths at the end of phototherapy (P = .038). A time trend for the relapse of symptoms within 12 and 18 weeks after completing phototherapy was significant for both visual analog scale scores but not for dermographometer-induced whealing.

Limitations: The apparent rarity of antihistamine-resistant symptomatic dermographism limited the study to a small number of participants. The severity of the condition did not permit a controlled and blinded study design.

Conclusions: NB UVB phototherapy is an effective second-line treatment for patients with severe symptomatic dermographism responding poorly to fexofenadine. This therapy can lead to subjective relief of pruritus and whealing and objective reduction of whealing. NB UVB phototherapy may restore symptom control with antihistamines in some patients.