Photodynamic Therapy May Be Effective for Uncommon Forms of Lichen Planus

PDT successfully treated uncommon and localized forms of recalcitrant lichen planus.

Photodynamic therapy (PDT) may be a treatment option for patients with uncommon forms of lichen planus (LP), researchers reported in a letter published in Dermatologic Therapy.

Investigators detailed their findings from 2 patients with uncommon forms of hypertrophic and erosive plantar LP that were successfully treated with PDT with use of Aktilite model CL128 (PhotoCure ASA) and methyl aminolevulinate (MAL) 16%. An identical treatment protocol was used for both patients, with a different frequency of sessions in patient 2. The incubation time of MAL was 3 hours, and the fluence was 37 J/cm2 in each session.

Patient 1 was a 69-year-old man with a 20-year history of generalized LP with skin lesions and erosive oral lichen planus. Previous treatment was unsuccessful. He also had a pinkish plaque with a white perifollicular coloration on the dorsum and palm of his right hand. A biopsy revealed hyperkeratosis with parakeratosis, acanthosis, and a band-like lymphohistiocytic infiltrate at the dermo-epidermal junction, as well as a cleft formation between the epidermis and papillary dermis and melanin pigment within macrophages of the dermis. He received clobetasol 0.5 mg/g and intralesional triamcinolone 40 mg/mL, which led to initial improvement but later progression. Red-light PDT with MAL 160 mg/g was initiated after the patient refused oral acitretin. Regional hand anesthesia and curettage were conducted before each session. Complete resolution of the lesion was achieved after 6 sessions (1 per month), and no side effects were reported.

In patient 2, a 42-year-old man presented with scaly and erosive lesions on the plantar feet with psoriasis. He received 6 months of treatment with clobetasol 0.5 mg/g combined with topical tacrolimus 0.1% and acitretin, but the lesions did not improve. A biopsy was consistent with erosive lichen planus. Red-light PDT with MAL 16% was administered every 2 months because the patient lived far away from the hospital. Paracetamol 1 g was administered before every session to try and reduce pain during the process. The patient had a decrease in the affected area and in pain when walking after 6 sessions. He discontinued the treatment due to severe pain during the process, and no other side effects were reported.

PDT can be considered as a novel treatment option for uncommon and localized forms of recalcitrant LP, due to the lack of side effects, wide availability, and promising results observed in our 2 cases.

PDT is based on the combination of light, oxygen molecules inside the targeted cells, and a photosensitizer agent, and several studies have shown positive results in oral lichen planus, including the erosive form. Narrowband ultraviolet B phototherapy and psoralen plus ultraviolet A phototherapy have been used successfully to treat patients with recalcitrant and disseminated LP, although they require more sessions than PDT, noted the researchers.

“PDT can be considered as a novel treatment option for uncommon and localized forms of recalcitrant LP, due to the lack of side effects, wide availability, and promising results observed in our 2 cases.”

References:

Fernández-Parrado M, Arostegui-Aguilar J, Perandones-González H, Hiltun I, de Dot-Gomara T, Larra-García M. Photodynamic therapy in uncommon forms of lichen planus. Dermatol Ther. Published online October 9, 2022. doi:10.1111/dth.15914