From the Research
Interstitial granuloma annulare is a rare variant of granuloma annulare that can be effectively managed with UVB/nbUVB/excimer laser therapy as a first-line treatment for patients with generalized disease, given its favorable long-term safety profile and higher response rates compared to other light therapies, as suggested by the most recent and highest quality study 1.
Overview of Interstitial Granuloma Annulare
Interstitial granuloma annulare is characterized by interstitial collagen degeneration and mucin deposition between collagen bundles in the dermis, presenting with flesh-colored to erythematous papules or plaques, often in an annular arrangement. The diagnosis relies on clinicopathological correlation, with a skin biopsy confirming the histological features of the disease.
Treatment Options
Treatment options for interstitial granuloma annulare include:
- Topical corticosteroids, such as clobetasol 0.05% ointment applied twice daily for 2-4 weeks
- Intralesional corticosteroid injections, such as triamcinolone acetonide 5-10 mg/ml
- Topical calcineurin inhibitors, like tacrolimus 0.1% ointment for smaller lesions
- Systemic therapies, including hydroxychloroquine (200-400 mg daily), dapsone (50-150 mg daily), or phototherapy, for widespread disease
Recommendation
Given the recent evidence from 1, UVB/nbUVB/excimer laser therapy is recommended as a first-line treatment for patients with generalized interstitial granuloma annulare, due to its effectiveness and favorable safety profile. Regular follow-up is recommended, as this condition may occasionally be associated with diabetes mellitus or thyroid disorders in some patients, as noted in 2 and 3.
Pathogenesis and Prognosis
The pathogenesis of interstitial granuloma annulare involves delayed-type hypersensitivity reactions with macrophages and T-lymphocytes causing collagen degradation, though the exact trigger remains unknown 2. Most cases are self-limiting and resolve spontaneously within 2 years, though recurrence is common. The generalized form is more chronic and less responsive to treatment, as mentioned in 3.