Annular Atrophic Lichen Planus Responds to Hydroxychloroquine and Acitretin

Comment

Lichen planus is a common pruritic inflammatory disease of the skin, mucous membranes, hair follicles, and nails with a highly variable clinical pattern and disease course that typically affects the adult population.² There are many clinical variants of lichen planus, which all demonstrate lichenoid dermatitis on histology. Annular lichen planus is an uncommon variant most commonly seen in men with asymptomatic lesions involving the axillae and groin.² Atrophic lichen planus is another variant demonstrating atrophic papules and plaques on the trunk and extremities.3 Annular atrophic lichen planus is the rarest variant of lichen planus, incorporating features of both annular and atrophic lichen planus.

The first case of AALP involved a 56-year-old black man with a 25-year history of annular atrophic papules and plaques on the trunk and extremities.¹ The second case reported by Requena et al⁴ in 1994 described a 65-year-old woman with characteristic lesions on the right elbow and left knee. Lipsker et al⁵ reported a third case in a 41-year-old man with a history of Sneddon syndrome who had lesions typical for AALP for 20 years. In all of these cases, histopathologic examination revealed a lichenoid infiltrate with thinning of the epidermis and loss of elastic fibers in the center of the active lesions.

In more recent cases of AALP, the characteristic findings primarily occurred on the trunk and extremities.^6-10 Treatment with topical corticosteroids failed in most cases and some patients noted moderate improvement with tacrolimus ointment 0.1%. Sugashima and Yamamoto¹¹ reported a unique case in 2012 of a 32-year-old woman with AALP on the lower lip. She had notable improvement with tacrolimus ointment 0.1% after 6 months.¹¹

All of the known cases of AALP to date have occurred in adults, both male and female, presenting with a limited number of annular plaques with slightly elevated borders and depressed atrophic centers.^1,3-11 Disease duration of AALP has ranged from 2 months to 25 years.¹¹ Histopathologic findings characteristically demonstrate a lichenoid dermatitis of the raised lesional border with a flattened epidermis, loss of rete ridges, and fibrosis of dermal papillae in the lesion center.⁷ The elastic fibers are destroyed in the papillary dermis of the lesion center, presumably due to elastolytic activity of inflammatory cells.¹ Macrophages present in the lichenoid infiltrate of acute lesions release elastases contributing to this destruction.⁷ Furthermore, elastic fibers appear fragmented on electron microscopy.¹

The clinical course of AALP has proven to be chronic in most cases and frequently is resistant to treatment with topical corticosteroids, retinoids, phototherapy, and immunosuppressive agents.³ Treatment administered early in the disease course may provide a more favorable outcome.¹¹ Lesions characteristically heal with scarring and hyperpigmentation. Our case displayed more extensive involvement than has previously been reported. Our patient showed minimal improvement with topical therapy; however, he demonstrated thinning and regression of active lesions after 2 months of combined treatment with hydroxychloroquine and acitretin. Our use of oral pentoxifylline, hydroxychloroquine, and acitretin has not been previously reported in the other cases of AALP we reviewed. Acitretin is the only systemic agent for lichen planus that has achieved level A evidence, as it previously was shown to be highly effective in a placebo-controlled, double-blind study of 65 patients.¹²

Conclusion

Annular atrophic lichen planus is a known variant of lichen planus characterized by a loss of elastic fibers in the papillary dermis in the center of active lesions. Treatment with topical corticosteroids and phototherapy frequently is ineffective. To our knowledge, there are no studies to date regarding the efficacy of systemic therapy in treatment of AALP. Hydroxychloroquine and acitretin may prove to be beneficial treatment options for resistant AALP. Additional alternative treatments continue to be explored. We encourage reporting additional cases of AALP to further characterize its clinical presentation and response to treatments.