The cause is unknown but is probably an inflammatory process induced by genetic or environmental factors. The primary target of inflammation in lichen planopilaris is the sebaceous or oil gland which is located at the same site as the stem cell region of the hair follicle. Recent research has shown that there is a defect in a “master regulator” protein called the peroxisome proliferator-activated receptor gamma, or PPAR gamma. PPAR gamma is responsible for in the preservation of hair follicle cells, including stem cells, and sebaceous glands. Loss of PPAR gamma leads to sebaceous gland dysfunction, which causes abnormal processing and buildup of “toxic” lipids. This abnormal buildup of lipids triggers inflammation that destroys the oil gland inflammation and the nearby stem cells, which are innocent bystanders. Once stem cells are destroyed, the follicles cannot regenerate, and permanent hair loss ensues.
It is not currently known if lichen planopilaris is truly an autoimmune disorder. Most leaders in the hair loss field feel as though it is not autoimmune, for several reasons: (1) it does not follow familial inheritance patterns of other autoimmune disorders. In other words, the disease arises quite sporadically and not in association with other known autoimmune disease. (2) The dramatic rise of lichen planopilaris in the last 10-20 years does not follow the incidence and prevalence trends for other autoimmune disorders. (3) No autoantibodies have been discovered yet for lichen planopilaris.
Signs & Symptoms
Lichen planopilaris affects primarily middle-aged women, but it can also affect men and individuals as young as teenagers.
Lichen planopilaris can be very symptomatic with intense burning, itching or tingling or it may be largely asymptomatic. Sometimes heavy shedding can be accompanied during periods of high disease activity. The course of lichen planopilaris is variable. It may evolve slowly with a few patches of hair loss or diffuse central hair thinning, which slowly progresses over many years. In other cases, the course is rapid, and within a few months many patches of hair loss or diffuse thinning spreads over large areas of the scalp. Although uncommon, some patients will have periods of time (remissions) when the disease is not active.
On clinical examination, the hair loss is either patchy or diffuse (or both). Typically, the top or crown of the scalp is initially affected, but lesions can occur anywhere on the scalp. Small bare patches may slowly coalesce with others and enlarge to involve large areas. In a typical active bare area, the center is smooth and devoid of follicular markings. Hair follicles around the margins of the bare areas show perifollicular erythema and perifollicular scale.
It has been recently recognized that hypothyroidism has been associated with LPP. Some patients with lichen planopilaris of the scalp, may also have other forms of lichen planus, most often oral and/or genital lichen planus. Occasionally patients will have cutaneous lichen planus which presents as very itchy purplish polygonal raised lesions on the trunk or extremities. Let your dermatologist know if you are suffering from other rashes, mouth sores or genital sores, in addition to your hair loss.
Diagnosis & Treatments
Detailed history, thorough physical examination of the scalp and interpretation of appropriate laboratory procedures, including scalp biopsies are necessary. Scalp biopsies are critical for the assessment and diagnosis of scarring hair loss and are often performed when considering a diagnosis of lichen planopilaris.
Early diagnosis and therapeutic intervention can often prevent permanent damage to hair follicles. Once a definitive diagnosis is made, we are able to determine the best treatment plan for each individual. Some regrowth is even possible with treatment.
Management of lichen planopilaris is complex. Treatment is case-dependent, based on severity of symptoms (itching and inflammation), findings on biopsy and extent of hair loss. Response to treatment varies from individual to individual. In general, very mild disease may be managed by topical corticosteroid solutions and foams and anti-inflammatory shampoos (such as tea tree oil). However, in most cases, topical treatments alone are not sufficient. The next step could be the addition of corticosteroid injections to the involved areas of the scalp, if the disease is localized to small areas. For more diffuse or severe cases, oral anti-inflammatory medications such doxycycline, methotrexate, dapsone, hydroxychloroquine (Plaquenil) or chloroquine (Aralen) are necessary to control the inflammation and destructive process. Rarely, immune suppressant drugs such as azathioprine (Imuran), mycophenolate mofetil (Cellcept) and cyclosporine are needed to achieve control. More recently, pioglitazone (Actos) an anti-diabetic drug which is a potent agonist for peroxisome proliferator-activated receptor-gamma (PPARγ), has shown some promising results. We encourage you to discuss these treatment options with your dermatologist.