Lichen planopilaris is a rare inflammatory condition that results in patchy progressive permanent hair loss mainly on the scalp.
Three forms are recognised:
- Classic lichen planopilaris, also known as follicular lichen planus
- Frontal fibrosing alopecia
- Graham Little syndrome
Diffuse hair loss is uncommon.
Who gets lichen planopilaris and why?
Lichen planopilaris usually affects young adult women, although the age range is wide and it also affects men. It commonly develops in association with lichen planus affecting the skin, mucosa and nails.
The cause of lichen planopilaris is unknown.
Although lichen planopilaris is rare, it is one of the common causes of scarring hair loss of the scalp.
Clinical features of lichen planopilaris
Lichen planopilaris typically presents as smooth white patches of scalp hair loss. No hair follicle openings can be seen in the areas of hair loss. At the edges of these patches there may be scale and redness around each hair follicle. Hairs can be easily pulled out. It is multifocal and small patches may merge to form larger irregular areas.
Common sites of involvement are the sides, front and lower back of the scalp.
Symptoms are often absent but they may include:
Lichen planopilaris is usually slowly progressive. Diffuse hair loss is uncommon.
How is lichen planopilaris diagnosed?
Lichen planopilaris is suspected on the clinical presentation and careful examination of the mouth, nails and skin for evidence of lichen planus elsewhere.
Trichoscopy reveals absent follicles, white dots, tubular perifollicular scale and perifollicular erythema.
The diagnosis may be confirmed on a scalp biopsy that includes hairs with surrounding redness and scale at the edge of an area of hair loss. Lichen planopilaris is an example of a primary lymphocytic folliculitis.
However it is not always possible to make a diagnosis on biopsy. Biopsy from an already scarred area of hair loss is unhelpful. Where there is only patchy scarring hair loss and no evidence of inflammation the diagnosis may not be able to be confirmed.