Generalized Granuloma Annulare Responsive to Narrowband UVB

To the Editor:

Granuloma annulare (GA) is a common dermatosis that usually presents with dermal papules and annular plaques in a symmetric distribution.¹ The etiology is unknown, but a delayed-type hypersensitivity reaction is the favored pathogenesis. Several systemic associations have been reported with generalized GA including diabetes mellitus, hyperlipidemia, autoimmune thyroiditis, rheumatoid arthritis, and lymphoproliferative malignancies, as well as other malignancies and viral infections such as human immunodeficiency virus and hepatitis C. Localized GA often is self-limiting, but generalized disease can be chronic and progressive. Although asymptomatic in most cases, the lesions can be cosmetically bothersome, and many patients desire treatment. There are few well-controlled studies of treatment, and most are limited to case reports and series. A review of GA treatment noted only 3 randomized studies: 2 relating to photodynamic therapy and 1 to cryosurgery. Well-accepted therapies, such as topical and intralesional corticosteroids, antimalarials, immunosuppressants, antibiotics, and phototherapy, are substantiated by lesser-quality evidence.¹ Phototherapy has been studied for the treatment of GA and other disorders with altered dermal matrix deposition for which there are limited effective treatment options. UV irradiation promotes degradation of structural components of the dermis and inhibition of collagen production.² Granuloma annulare generally is resistant to therapy. We report a case of generalized GA of long duration that responded well to phototherapy with narrowband UVB (NB-UVB).

A 60-year-old woman presented with generalized GA of 4 years’ duration that was confirmed on biopsy on 2 occasions (Figure 1). The lesions were asymptomatic but disfiguring and consisted of extensive pink, thin, annular plaques and papules on the torso, arms, and legs (Figure 2A). Apart from mild depression for which she was being treated with paroxetine and trazodone, she was otherwise healthy without evidence of thyroid disease, hyperlipidemia, or diabetes mellitus. Prior treatments for GA had included tapering courses of prednisone (up to 30 mg/d, tapered by 5 mg every 4 days) and betamethasone dipropionate cream 0.05%. She was started on NB-UVB therapy 5 times weekly in incremental doses with no adjuvant therapy. After 100 treatments, there was notable improvement with lesions becoming paler and flatter, with some involuting completely (Figure 2B). The frequency of treatment was reduced to 3 times weekly with continued improvement. An NB-UVB device was used containing 48 TL 100W/01-FS72 lamps with a mean irradiance of 2.9 mW/cm². Her starting dose was 90 mJ/cm². The cumulative dose after 100 treatments was 35,600 mJ/cm². Apart from occasional mild erythema, there were no adverse effects.

Figure 1. Granuloma annulare. Plump histiocytes arranged in a palisaded fashion around foci of incomplete collagen degeneration associated with moderate perivascular lymphocytic infiltrate and basket weave horn in the epidermis (H&E, original magnification ×100).

Figure 2. Granuloma annulare. A, Extensive pink, thin, annular plaques and papules on the left lateral thigh before phototherapy. B, Notable improvement was seen after 100 narrowband UVB phototherapy treatments.