BC04: Treatment and outcomes for lichen planus pigmentosus: a literature review

Posters

Wajeeha Khan,¹ Sanna Fatima² and Muhammad Javed³

¹Chapel Allerton Hospital, Leeds, UK; ²Sutter Hospital, Antioch, CA, USA; and ³Wellington Hospital, London, UK

Lichen planus pigmentosus (LPP) is an atypical and uncommon macular variant of lichen planus that creates considerable cosmetic distress in patients. Its morphology ranges from bluish-grey to brownish-black coalescing macules most commonly on sun-exposed areas. The natural course varies with spontaneous resolution in some cases and persistence of pigmentation in others. This review provides an update and summarizes the currently available evidence related to treatment and clinical outcomes of LPP. A PubMed search was performed for studies addressing LPP treatment between 2010 and 2020. A total of 102 patients (two nonrandomized prospective studies, five retrospective case series and seven case reports) were treated with different treatment modalities. Mean age was 35 years and follow-up ranged from 3 to 12 months. The commonest site was the face (79%). Sixty-four per cent of patients were of Indian ethnicity followed by European (20%) and Arabic or East-Asian ethnicity. Overall, 10 different strategies and combinations were used for treatments. The most common topical treatment used was tacrolimus cream (24%). This treatment, when used as a single agent with a low potency (0·03%) for 4 months, achieved a pigment reduction of > 75% in 13 patients. However, when used with higher potency (0·1%) in combination with Nd:YAg laser (n = 3) achieved excellent results (> 75% pigment reduction) in all cases. In contrast, Nd:YAg laser was used alone in nine patients and achieved only 25% improvement. In six patients a combination treatment of tacrolimus (0·1%) + 2·5 mg pulsed dexamethasone and topical mometasone for up to 16 weeks helped with disease stabilization. Tacrolimus (0·1%) and oral dapsone combined therapy was used to control progression in five patients. Oral treatment with isotretinoin (20 mg) achieved a > 50% pigment reduction in 35% cases when used up to 6 months (n = 27) and 9 months (n = 1). When transexamic acid (250 mg once daily) was used over 4–6 months, a partial improvement was seen in 50% (n = 20) of cases. Other treatments such as chemical peel with croton oil-free phenol (six sessions over 3 weeks) achieved > 75% pigment reduction in 23·5% (n = 4/17) of patients. Narrowband ultraviolet B in a 13-year-old achieved an excellent result, and oral colchicine for 6 months in another patient on a weaning regimen achieved moderate results. No major side-effects were reported with any treatment. The best clinical outcomes were achieved by confirming histopathological diagnosis, including assessment of depth of pigmentation and achieving control of disease activity by using topical or oral immunomodulators. Refractory hyperpigmentation is seen due to the presence of deep dermal melanophages, which are difficult to treat with immunomodulators alone. This can be effectively managed by employing chemical peels and laser. In conclusion, LPP treatment remains a therapeutic challenge and further prospective trials with head-to-head comparisons are needed to further elucidate the treatment regimens.