Lichen Planus: Symptoms, Causes, and Treatment via UK Online Doctor

Lichen planus is a relatively common inflammatory condition that can affect the skin, the lining of the mouth (oral lichen planus), and occasionally the nails or scalp. In the UK, it is estimated to affect around 1% of the population. It is famously characterised by the 'six Ps': planar (flat-topped), purple, polygonal, pruritic (itchy), papules, and plaques.

Unlike many rashes that may look similar, lichen planus is not caused by an infection, is not a form of cancer, and cannot be passed from person to person. It is generally considered an autoimmune-related condition where the body's immune system mistakenly attacks the skin or mucosal cells. While the exact trigger is often unknown, it can sometimes be linked to certain medications or underlying health conditions.

The symptoms of lichen planus can vary depending on which part of the body is affected. On the skin, it typically appears as shiny, flat-topped bumps that are firm to the touch. These bumps often have a purple or reddish hue and may be crossed by fine white lines, known as Wickham striae.

Common areas affected:

• Wrists and Ankles: Often the first places the rash appears.
• The Mouth: Known as oral lichen planus, this presents as a white, lacy pattern on the inside of the cheeks or tongue. It can sometimes cause painful ulcers.
• The Torso: The rash can spread across the lower back or abdomen.
• Nails: Lichen planus can cause ridges, thinning, or even the loss of fingernails and toenails.
• The Scalp: In rare cases, it causes redness and hair loss (lichen planopilaris).

The most distressing symptom for many British patients is the intense itching, which can interfere with sleep and daily activities. Unlike eczema, the skin surface is usually shiny rather than dry or scaly.

According to NHS and NICE Clinical Knowledge Summaries, the exact cause of lichen planus is not fully understood. However, it is widely accepted as an immune-mediated disease. This means the body’s white blood cells, which usually fight off viruses and bacteria, start attacking the skin cells.

In some cases, lichen planus can be triggered by external factors. These may include:

• Medications: Certain medicines for high blood pressure, heart disease, or arthritis can trigger a 'lichenoid' reaction.
• Metal Fillings: Occasionally, oral lichen planus is triggered by an allergy to mercury in dental amalgam.
• Hepatitis C: There is a statistical link between patients with Hepatitis C and the development of lichen planus, though this is less common in the UK than in other parts of the world.
• Stress: While not a direct cause, many patients report that emotional stress can lead to a flare-up of symptoms.

Diagnosis is usually made based on the clinical appearance of the rash. A GP or online doctor will look for the characteristic purple hue and Wickham striae. If you have patches in your mouth as well as your skin, this further supports the diagnosis.

In cases where the diagnosis is uncertain, or if the symptoms are particularly severe, a small skin biopsy may be required. This involves taking a tiny sample of the affected skin under local anaesthetic to be examined under a microscope. Most patients, however, can be diagnosed and managed based on a physical or visual assessment.

While lichen planus often resolves on its own within a year or two, many patients require treatment to manage the discomfort and speed up recovery. Following NICE guidelines, the first line of treatment typically involves:

Topical Corticosteroids

Strong steroid creams or ointments, such as clobetasol propionate or betamethasone, are often prescribed to reduce inflammation and calm the immune response in the skin. For oral lichen planus, specialist mouthwashes or pastes may be used.

Antihistamines

If the itching is severe and affecting your sleep, a non-sedating antihistamine during the day or a sedating antihistamine at night may be recommended by your GP.

Self-Care Measures

Patients are advised to avoid washing with harsh soaps; instead, use soap substitutes or emollient creams to avoid further irritating the skin. If you have oral lichen planus, avoiding spicy, acidic, or salty foods can help prevent pain.

If you notice a new, unexplained rash that is purple, itchy, or persistent, seeking medical advice is essential. You should consult an online doctor if:

• Self-care measures and over-the-counter creams are not providing relief.
• The rash is spreading rapidly across your body.
• You have painful sores or white patches in your mouth that make eating difficult.
• The condition is affecting your scalp or nails, which may lead to permanent scarring or hair loss if untreated.

An online GP consultation provides a convenient way to have your skin assessed via high-quality photos and video. This allows for a prompt diagnosis and the issuance of a private prescription for effective treatments like potent steroid creams, which are not available over-the-counter in the UK.