Psoriasis therapy. The effect of UV radiation on sensitization to mechlorethamine

Abstract

A study was performed to determine the effect of UV-B radiation on the sensitization of patients to topically applied mechlorethamine hydrochloride. Patients with widespread psoriasis were randomized into two groups. One group was given six daily treatments of one minimal erythemal dose (MErD) prior to starting daily applications of a 0.02% mechlorethamine ointment and, thereafter, one MErD weekly; the other group was given daily applications of mechlorethamine but received no UV-B. The improvement of psoriasis was monitored by a severity score system and patients were treated for 30 days, or until contact dermatitis occurred. The addition of UV-B to topical applications of mechlorethamine reduced the incidence of allergic contact dermatitis to mechlorethamine from 64% to 22%. In those sensitized to mechlorethamine, the time required for sensitization to develop was increased from 14 to 23 days by UV-B therapy.

A Prospective Study of Cutaneous Intolerance to Topical Mechlorethamine Therapy in Patients With Cutaneous T-Cell Lymphomas

“…Of the 23 patients with CIM in our study, CIM occurred within the first month of treatment with mechlorethamine in 13 (56%) and within 3 months in 21 (91%). These data are similar to that of previous reports 6,7,9,11,19 that CIM usually occurs in the first weeks of mechlorethamine treatment.…”

“…In patients with psoriasis, it has been shown that intravenous desensitization to mechlorethamine is unsuccessful. 10 Therapy with UV-A or UV-B can reduce the incidence of allergic contact dermatitis caused by mechlorethamine therapy 11 and delays contact sensitization to mechlorethamine. 12 In patients with MF, there is no clear evidence that the use of PUVA therapy delays the development of mechlorethamine sensitization.…”

PUVA therapy prevents sensitization to mechlorethamine in patients with psoriasis

“…With respect to the prevention of allergic dermatitis to mechlorethamine, we obtained similar results with PUVA to those of Nusbaum et al (1983) with UV-B. We did not find the combination of PUVA and mechlorethamine more efficient than PUVA alone in clearing psoriasis (Ortonne et al, 1977).…”

“…In this study patients were not randomized, varying doses of UV were given before starting mechlorethamine and UV therapy was discontinued at varying intervals after commencing mechlorethamine. Nusbaum et al (1983) studied 20 psoriatic patients randomized into two groups. In one group G.Mauduit, O.Silvestre and J.Thivolet mechlorethamine ointment was used alone and in another group patients were treated with mechlorethamine daily after six UV-B treatments.…”

“…It has been reported that a diminished allergic contact reaction can be achieved by treatment of the skin with UV radiation (Morison et al, 1981). In patients with psoriasis, sensitization to mechlorethamine may be prevented by UV-B (Nusbaum et al, 1983).…”