The quality of evidence is downgraded by study limitations (unclear allocation concealment), by indirectness (differences between the outcomes of interest and those reported: only short-term outcomes reported), and by imprecise results (few patients and outcome events).
A Cochrane review included 5 studies with a total of 197 subjects. Interventions in the 5 studies were topical steroids, hydroxychloroquine, acitretin, topical salbutamol, topical tacrolimus, and topical pimecrolimus. Complete resolution of skin lesions was seen in 27% of people using fluocinonide 0.05% cream and in 10% of those using 1% hydrocortisone cream in one 6-week study (RR 2.77, 95% CI 0.95 to 8.08; 1 study, n=78).
In a study comparing acitretin 50 mg daily and hydroxychloroquine 400 mg daily in 58 people, there was complete resolution in 46% of people using acitretin and in 50% of people using hydroxychloroquine (RR 0.93, 95% CI 0.54 to 1.59). Clearing of erythema in at least 50% of lesions was reported in 42% on acitretin and 68% on hydroxychloroquine (RR 0.61, 95% CI 0.36 to 1.06, 1 study, n=49). The main adverse effects were dry lips (93% of the acitretin group and 20% of the hydroxychloroquine group) and gastrointestinal disturbance (11% of the acitretin group and 17% of the hydroxychloroquine group). Four participants on acitretin withdrew due to gastrointestinal events or dry lips.
One study (n=10) compared a calcineurin inhibitor, pimecrolimus 1% cream and betamethasone 17-valerate 0.1% cream, and another study (n=14) compared tacrolimus cream 0.1% with placebo (vehicle), but these studies reported none of the primary outcome measures. Topical R-salbutamol 0.5% cream was compared with placebo (vehicle) over 8 weeks in one study (n=37). There was a significant improvement in pain and itch in the salbutamol group at 2, 4, 6, and 8 weeks compared to placebo, but the study did not record a formal measure of quality of life. None of the primary outcome measures were reported.
A Cochrane review