Lichen planopilaris (LPP) is an uncommon inflammatory condition that targets the hair follicles on the scalp, leading to permanent hair loss. It is classified as a primary scarring alopecia, meaning it causes irreversible damage to the structures responsible for hair growth. LPP is one of the most frequently diagnosed causes of scarring hair loss. Early identification and intervention are important because the damage inflicted by the inflammation cannot be reversed once scarring occurs, making the preservation of existing hair the main goal of management.
Defining Lichen Planopilaris
Lichen planopilaris is a form of cicatricial alopecia, the medical term for hair loss characterized by scarring. The underlying pathology involves an inflammatory attack that targets the upper part of the hair follicle, known as the bulge area. This region contains the stem cells essential for regenerating the hair shaft and the sebaceous gland.
The inflammation, dominated by specialized immune cells called T-lymphocytes, destroys these stem cells and the surrounding follicular unit. As the hair follicle is destroyed, the structure is permanently replaced by dense, fibrotic tissue. This process prevents any future hair growth from that follicle, resulting in the characteristic permanent hair loss of LPP.
LPP presents in a few distinct clinical patterns. The classic form typically causes patchy areas of hair loss on the sides, front, and top of the scalp. Frontal fibrosing alopecia (FFA) is a common variant characterized by a band-like pattern of hair loss along the front hairline, often including the loss of eyebrows. A third variant is Graham-Little-Piccardi-Lasseur syndrome, which combines scalp scarring alopecia with non-scarring hair loss in the armpits and pubic area.
Recognizing the Clinical Signs and Diagnosis
Patients often first notice symptoms like itching, burning, tenderness, or pain in the scalp, a sensation medically referred to as trichodynia. The visual signs typically present at the edges of the hair loss patches, indicating areas where the disease is actively destroying follicles.
A characteristic finding is perifollicular erythema, which is redness surrounding the base of the hair follicle, along with scaling. This scaling is a buildup of keratinized material around the hair shaft. The affected areas of hair loss appear smooth and shiny, and close examination reveals the absence of visible hair follicle openings, confirming destruction and scarring.
Diagnosis requires a combination of clinical assessment, specialized imaging, and a definitive tissue sample. Dermatologists frequently use a dermatoscope (or trichoscope) to closely examine the scalp, which can reveal signs of perifollicular redness and scaling.
The standard for confirming LPP is a scalp biopsy, where a small tissue sample is surgically removed from an active area for laboratory analysis. Microscopic examination of this tissue reveals a specific pattern of inflammation that helps differentiate LPP from other types of hair loss. Timely diagnosis is important because LPP signs can overlap with non-scarring conditions, making the biopsy necessary to ensure the correct treatment path is chosen.
Understanding the Underlying Causes
The precise reason LPP develops remains unknown, but it is classified as an autoimmune disorder. This means the body’s own immune system mistakenly launches an attack against healthy tissue, specifically targeting the hair follicle.
The prevailing theory is that activated T-lymphocytes, which are part of the adaptive immune system, begin to target an unknown antigen within the hair follicle structure. This targeted attack leads to a cytotoxic response against the follicular cells. Researchers have also noted that some individuals with LPP have lower levels of a protein called PPAR gamma, which is important for maintaining the health of hair follicles.
While the singular cause is idiopathic, several factors are proposed as potential triggers. Possible risk factors include a genetic predisposition, as some patients have differences in certain immune-related genes. Environmental factors like specific medications, viruses, or contact allergens have also been suggested as potential agents that might initiate the immune response.
LPP predominantly affects women, particularly those who are middle-aged. This suggests that hormonal shifts, such as those occurring around menopause, may play a role, especially in the frontal fibrosing alopecia variant.
Management and Treatment Options
Treatment for Lichen Planopilaris focuses on halting the inflammatory process to prevent further destruction of hair follicles. The approach is tailored to the individual, depending on the extent of hair loss, the severity of symptoms, and the progression rate of the condition.
First-line therapies often involve anti-inflammatory medications applied directly to the scalp. High-potency topical corticosteroids, such as foams, solutions, or creams, are frequently prescribed to suppress immune activity in active areas. For more concentrated inflammation, intralesional corticosteroids can provide a more powerful anti-inflammatory effect.
Another topical option is calcineurin inhibitors, such as tacrolimus, which suppress the localized immune response without the potential side effects associated with long-term steroid use.
Systemic Medications
When LPP is widespread, rapidly progressing, or unresponsive to topical treatments, systemic medications taken orally may be necessary. The anti-malarial drug hydroxychloroquine is a common systemic treatment used for its immune-modulating properties. Oral antibiotics, particularly doxycycline, are also used for their anti-inflammatory action to help reduce redness and irritation on the scalp.
If the disease continues to progress, a dermatologist may consider stronger immunosuppressive agents. These are reserved for severe or widespread cases to suppress the overall immune response:
- Methotrexate
- Cyclosporine
- Mycophenolate mofetil
- Pioglitazone, a medication originally for diabetes, which has shown promise in reducing symptoms and inflammation.
Managing discomforting symptoms like itching and burning is an important part of the treatment plan. For patients whose disease has been inactive and stable for a significant period, surgical options may be considered. Hair transplantation or scalp reduction surgery can be performed, though there is a risk of LPP recurring in the transplanted area.