Pityriasis Lichenoides: Chronica and Et Varioliformis Acuta (PLEVA) UK Guide

Pityriasis Lichenoides is an uncommon skin disorder that manifests as crops of small, firm, reddish-brown spots. These spots may be itchy or painful and often develop a fine scale. Unlike many other dermatological conditions, it is not infectious and cannot be passed from person to person. In the UK, it is most frequently observed in children and young adults, though it can affect people of any age.

Doctors categorise the condition into two distinct types: Pityriasis Lichenoides et Varioliformis Acuta (PLEVA) and Pityriasis Lichenoides Chronica (PLC). PLEVA is the more severe, sudden-onset version, often characterised by blisters and crusting, while PLC is more gradual, resulting in flatter, scaly patches that may leave behind light or dark marks on the skin.

Symptoms of PLEVA

PLEVA typically appears quite suddenly. Patients may notice small red spots that rapidly evolve into blisters or fluid-filled sacs. These can break down into ulcers or crust over, sometimes resembling chickenpox. These lesions can be itchy or even stinging and may take several weeks to heal, often leaving behind small scars.

Symptoms of PLC

Pityriasis Lichenoides Chronica is much more subtle and long-lasting. The spots are usually brownish-pink and covered with a firm, 'mica-like' scale that can be peeled off to reveal a shiny pink surface. The lesions in PLC are not usually painful or ulcerated, but the condition can last for many months, with new crops of spots appearing as old ones fade.

Both conditions commonly affect the trunk (chest, back, and stomach), thighs, and upper arms, but they rarely appear on the face or scalp.

The precise cause of Pityriasis Lichenoides remains a subject of ongoing clinical debate among dermatologists in the UK. However, the prevailing theory, aligned with NHS and British Association of Dermatologists (BAD) guidance, suggests it is an inflammatory response by the immune system (specifically T-cells).

Possible triggers often cited include:

• Infection: Some cases seem to follow a viral or bacterial infection, such as the flu or streptococcal throat infections.
• Immune response: The body may be reacting to an unidentified external agent.
• Hypersensitivity: A reaction to certain medications or environmental factors.

It is important to note that it is not caused by poor hygiene and is not a form of skin cancer, though it requires professional diagnosis to rule out more serious conditions.

According to NICE clinical knowledge summaries, many mild cases of PLC do not require intensive treatment and will eventually resolve spontaneously. However, for symptomatic patients or those with PLEVA, several options are available:

• Topical Steroids: These creams or ointments help reduce inflammation and itching.
• Oral Antibiotics: Medications like erythromycin or tetracycline are often prescribed not just to kill bacteria, but for their anti-inflammatory properties, which can help clear the rash.
• Phototherapy: Narrowband UVB light therapy, usually administered in a hospital dermatology department, can be highly effective for widespread cases.
• Moisturisers (Emollients): Keeping the skin hydrated can reduce the discomfort and scaling associated with PLC.

Because Pityriasis Lichenoides can look very similar to other conditions like guttate psoriasis, pityriasis rosea, or even certain STI-related rashes, getting a professional opinion is vital. Speaking to an online GP is a convenient first step for UK patients. During a video consultation, a doctor can examine the rash, discuss your medical history, and help determine if the symptoms match the profile of Pityriasis Lichenoides.

An online doctor can:

• Provide an initial diagnosis and ease anxiety regarding the nature of the rash.
• Issue private prescriptions for topical treatments or antibiotics if appropriate.
• Advise on whether a referral to a secondary care dermatologist is required for phototherapy or a skin biopsy.
• Issue sick notes if the discomfort of PLEVA is affecting your ability to work.

While awaiting medical review or during treatment, there are several steps you can take to manage Pityriasis Lichenoides at home. Firstly, avoid scratching the lesions, as this can lead to secondary bacterial infections and increased scarring. Use mild, fragrance-free cleansers instead of harsh soaps, which can further irritate the skin.

Wearing loose-fitting cotton clothing can also reduce friction on the spots. If your skin is particularly itchy, cool baths or using a damp flannel may provide temporary relief. Documentation is also helpful; taking clear photos of the rash over several weeks can assist your GP or dermatologist in tracking the progression from acute to chronic stages.