Recovery from tanning induced by narrow-band UVB phototherapy in brown-skinned individuals with psoriasis: twelve-month follow-up

Abstract

Background: Pigmentation induced by narrow-band UVB (NBUVB) phototherapy can cause complaints by psoriasis patients, especially those with brown skin. Nevertheless, the recovery process from tanning after the completion of NBUVB treatment is not known.

Objective: The purpose of this study was to evaluate the extent of tanning recovery after the end of NBUVB treatment and determine the time required to recover from the fully tanned state.

Method: Sixteen psoriasis patients with brown skin were observed. The skin color changes on the lower back were measured before beginning phototherapy, upon completion of NBUVB treatment, and subsequently every month for the first one-half year, then bimonthly for the second one-half year, using two different reflectance spectrophotometers. The results are presented as the erythema index (EI) and melanin index (MI), L*a*b* values as recommended by the Commission Internationale de l'Eclairge, and the individual typology angle (ITA degrees).

Results: The mean L* value reached 64.4 by the 10th month after the end of NBUVB treatment, with no significant difference from the value before beginning phototherapy. The mean ITA degrees approximated the initial angle at the 8th month after completing NBUVB treatment with no significant difference, thus representing recovery to the original intermediate skin color. The MI recovered to the initial values earlier than the L* value and ITA degrees. The EI appeared the earliest recovery value.

Conclusion: Understanding the recovery process from tanning induced by NBUVB treatment will improve the patient's compliance for treatment and bring higher efficacy and safety to the retrial of phototherapy in brown-skinned individuals with psoriasis.