Phototherapy of granuloma annulare: a single center retrospective study

Granuloma annulare is a chronic, benign skin condition characterized by small erythematous patches, plaques or papules in annular or disseminated order. Due to the cosmetic impact, many patients experience a significant level of distress. Nevertheless, selecting the optimal treatment method often poses a challenge due to the limited available data. A remission of skin lesions can be achieved through topical, systemic, or intralesional therapies, and various forms of phototherapy.

This retrospective study included 58 patients diagnosed with granuloma annulare and evaluated a total of 73 cycles of phototherapy (UVA-1, oral-PUVA, bath-PUVA) concerning treatment response and adverse events. It was conducted at the outpatient phototherapy clinic of the University Department for Dermatology and Venereology, Medical University of Graz. The Data was collected over the period from February 2011 and February 2021.

Complete response was achieved in 37.5% of the 16 bath-PUVA therapy cycles, 25.7% of the 35 oral-PUVA therapy cycles, and 35.3% of the 17 UVA-1 therapy cycles. Partial response was noted in 62.5% of the oral-PUVA therapies, 50% of the bath-PUVA therapies, and 41.2% of the UVA-1 therapies. Generally, the adverse events of phototherapy were mild, with the highest incidence of adverse events associated with oral-PUVA and the lowest with UVA-1 therapy.

No significant differences in efficacy were found between UVA-1 therapy, oral-PUVA, and bath-PUVA. However, UVA-1 therapy resulted in the fewest adverse events. Given the frequent occurrence of recurrences, the risk-benefit profile of each therapy should be carefully assessed in advance.