Comparing the efficacy of 50% dimethyl sulfoxide solution versus topical tretinoin 0.5% cream in patients with cutaneous amyloidosis

The present study was designed to compare the efficacy of 50% dimethyl sulfoxide topical solution versus tretinoin 0.5% cream in treating primary localized cutaneous amyloidosis.

Split-side, own control, double-blinded controlled clinical trial

Ten patients (three iterations on type I error of 5%, Zα/2 = 1.96, Zβ = 0.84) with primary cutaneous amyloidosis refer to dermatology clinics, Faghihi hospital, Shiraz, will enroll. Although the treatments will be allocated randomly, the patients are aware of the treatments. The blinded principal dermatologist measures baseline melanin, erythema, and itching quantitative values at baseline for each side separately. Patients receive dimethyl sulfoxide 50% topical solution and tretinoin 0.5% cream on the assigned side for twenty weeks. They instruct by a blinded dermatologist to apply treatments daily in the first four weeks and every other day later on. Patients reattend the Faghihi hospital dermatology clinic and further colorimetery, itching scoring, and photography undertake at the end of 4th, 12th, and 18th week follow ups with the dermatologist unaware of the treatments’ side.

Patients will include if they have bilateral macular or lichen amyloidosis, confirmed by H&E staining, and were over 18 years of age. Volunteers will exclude from the study if they have hypersensitivity to retinoids, are taking topical agents in recent four weeks, are pregnant or lactating, are hepatic disorders, or have not consent to photography.

Patients receive dimethyl sulfoxide 50% topical solution (intervention, formulized and prepared at the School of Pharmacy, Shiraz) and tretinoin 0.5% cream (control, Iran Daroo, Tehran, Iran) on the assigned side daily for 4 weeks and every other day to the 20th week..

melanin; erythema; itching score.

We use simple randomization by the random number table in order to generate random sequence. To this end, a biostatistician employs the random allocation software and after obtaining the reading trend, the first number will assign to the right side and the second number will assign to the left side. The odd number and even number represent the intervention and control sides, respectively. Therefore, dimethyl sulfoxide and tretinoin will be assigned for each side (right or left). Then, allocation concealment will be done using SNOSE method and numbered, sealed and opaque envelopes by a medical doctorate candidate will be sequenced and will be delivered to the principal dermatologist. In time of enrolling the participants to the study who is fulfilled the inclusion criteria, evaluated by the dermatologist, two consecutive envelops will be open and the allocated sides will be obtained. Each patient will serve as his/her own control; by doing so, the problem of confounding factor will be avoided. Also, for concealment, we will use similar containers in shape and color.

Although the treatments were allocated randomly, the patients were aware of the treatments (dimethyl sulfoxide solution and tretinoin cream can be distinguished). They instructed by a blinded dermatologist (Researchers will be blinded to the allocation until the end of study. To conceal group allocation, we use similar containers in shape and color) to apply treatments daily in the first four weeks and every other day later on. Notably, tubes are identical and based on list and number on tubes, will be assigned to each side in every patient. Also, the baseline outcomes will record. Patients reattended and further colorimetery, itching scoring, and photography were then undertaken at the end of 4th, 12th, and 18th week follow ups with the dermatologist unaware of the treatments’ side which the volunteer had been randomized. َAdditionally, dermatologist will record the outcomes as well. Data analysis will be done by an epidemiologist who is unaware of treatments.

There is no further information.