Lichen Planopilaris
Definition: Lichen Planopilaris (LP) is an inflammatory primary cicatricial alopecia that can result in permanent hair loss. LP is a follicular variant of lichen planus that results in progressive, patchy and permanent hair loss on the hair-bearing skin surfaces.
Etiology: LP is believed to be a hair-specific autoimmune disorder caused by activated T-lymphocytes targeting follicular antigens. This is theorized to be a part of a cytotoxic autoimmune response to an unknown antigen present in hair follicles. The use of nilotinib and pembrolizumab has been linked to LP.
Epidemiology: The incidence of LP is not precisely known. LP has been reported as the most frequent primary scarring alopecia. Variants of LP include Graham-Little syndrome and frontal fibrosing alopecia. LP often affects women more than men. The peak age range of LP is between 40- 60 years.
Signs: Many individuals with LP may develop characteristics affecting the skin, mucous membranes and nails. LP typically presents as multifocal areas with smooth white patches of scalp hair loss. There may be perifollicular erythema and perifollicular scale at the edge of the patches, and these may be spiny upon palpation. There may be cutaneous, nail and mucous membrane involvement before LP manifests on the scalp. Hairs may be easily extracted anywhere on the scalp, indicating active disease requiring treatment. The clinical course of hair loss in LP may be insidious or fulminant. Clinical features of LP do not vary in different skin types. Complications of LP include alopecia, psychological distress and reduced quality of life.
Symptoms: Individuals with active LP may experience severe itching, burning and tenderness.
Differentials: Discoid lupus erythematosus, folliculitis decalvans, central centrifugal cicatricial alopecia, seborrheic dermatitis.
Diagnosis: LP is assessed using trichoscopy, which reveals absent follicles, tubular perifollicular scale, white dots and perifollicular erythema. Diagnosis may be confirmed through scalp biopsy
Treatment: as no treatment restored the original hair loss due to scarring, treatment aims to slow the progression of LP and relieve its associated symptoms. Anti- inflammatory agents such as corticosteroids, tacrolimus and hydroxychloroquine may be indicated. Non pharmacological measures include scalp reductions and hair transplantation in end- stage inactive disease.
References:
1. Lepe K, Nassereddin A, Syed HA, Salazar FJ. Lichen Planopilaris. In: StatPearls. Treasure Island (FL): StatPearls Publishing; May 1, 2024.
- Lichen Planopilaris — DermNet. dermnetnz.org. https://dermnetnz.org/topics/lichen-planopilaris