Lichenoid Keratosis Diagnosis and Management in London

What is Lichenoid Keratosis?

Lichenoid keratosis describes a benign inflammatory reaction that most commonly arises in a pre‑existing sun‑induced spot (a solar lentigo) or a seborrhoeic keratosis. In simple terms, the immune system is “editing” an older lesion. This process can make the area appear pinker, greyer or variegated in colour and, because of those changes, the lesion can resemble precancerous AK, BCC or very early melanoma. LK does not turn into skin cancer, but lookalike risk means proper dermatology review is wise.

Why does it happen? (Causes & Pathology)

The exact trigger is not fully understood. Current evidence suggests a localized immune‑mediated regression of a pigmented lesion in sun‑exposed skin. Over years, UV light alters epidermal cells and pigment distribution. At some point, the immune system recognizes changes within an older lentigo or seborrhoeic keratosis and mounts a lichenoid (interface) reaction—hence the name. This produces a small inflammatory plaque with a range of colours (pink, tan, grey “peppering”), often smoothing out and fading gradually over time.

Where on the body does LK occur?

Most commonly on sun‑exposed areas: upper chest, shoulders, forearms and back; occasionally the face. It is usually solitary, but some patients develop more than one over time, especially where cumulative UV exposure is higher.

What does LK look and feel like?

• A small papule or thin plaque, pink, red‑brown or grey‑brown.
• Often flat‑topped with a fine, slightly scaly surface.
• May be tender or itchy, though many are asymptomatic.
• Colour drift over weeks to months as inflammation settles (e.g., pink → tan → light grey).
• Commonly arises where a previous “age spot” or “stuck‑on wart” (seborrhoeic keratosis) existed.

When to seek review: Any lesion that rapidly enlarges, bleeds spontaneously, develops irregular borders/colours, or looks different to others (the “ugly duckling”) should be assessed—our ABCDE mole check explains warning signs.

How we diagnose LK safely

Your dermatologist first examines the lesion in good light, then uses dermatoscopy (magnified polarised imaging) to look for characteristic structures: peppering (grey dots), subtle regression areas, remnants of a lentigo or seborrhoeic keratosis, and a lack of malignant networks. If any red flags are present or the pattern is atypical, a small edge biopsy is recommended. Histology in LK shows a lichenoid interface dermatitis with melanophages (pigment‑eating cells) and signs of regression—findings that distinguish LK from melanoma or BCC.

Where pigment questions remain, we may complement assessment with digital skin analysis or, rarely, Wood’s lamp to visualise superficial pigment patterns.

Conditions that mimic LK (and vice‑versa)

Treatment options (often: reassurance)

Because LK is benign, many patients choose no active treatment once the diagnosis is confirmed. For symptoms or cosmetic reasons, we discuss:

• Watchful waiting: Many lesions fade gradually over months.
• Short topical steroid course: To settle itch/tenderness and reduce visible inflammation.
• Cryotherapy: Brief liquid‑nitrogen freeze for selected LK—can lighten or remove the lesion. Risk of temporary pigment change, particularly in darker skin tones.
• Gentle curettage/shave removal: Considered when diagnosis is secure and patient prefers removal (e.g., recurrent friction).

If dermoscopy/biopsy suggests a different diagnosis (e.g., AK, BCC), we will explain appropriate next steps or refer within our precancerous & cancerous lesions treatment pathway.

Sun, pigment and scar considerations

LK occurs where cumulative UV is higher. Adopting daily broad‑spectrum SPF 30+, UV‑protective clothing and shade habits helps reduce new sun‑damage changes. After cryotherapy or removal, transient hypo‑ or hyper‑pigmentation can occur, especially in skin of colour; care plans are tailored accordingly and may include gentle skincare. If pigment marks persist and are bothersome, our clinicians can discuss conservative options within the hyperpigmentation treatment service when appropriate.

Living with Lichenoid Keratosis: practical tips

• Photograph the lesion in good light every 4–6 weeks to track changes.
• Minimise friction from backpacks or bra straps over chest/shoulder lesions.
• Daily SPF 30+ on exposed areas; reapply outdoors and wear a hat on bright days.
• Don’t pick or scratch—picking prolongs inflammation.
• Schedule review if it enlarges, becomes asymmetric, bleeds, or you develop a new “different” lesion—see ABCDE guidance.

Your first visit — what to expect

1. History: How the lesion started/changed, sun exposure, personal/family history of skin cancer or atypical moles.
2. Examination: Clinical check plus dermatoscopy to identify LK features and rule out lookalikes.
3. Investigations (if needed): Small biopsy where pattern is atypical.
4. Plan: Reassurance/watchful waiting vs. simple treatment (e.g., cryotherapy) depending on findings and preference.
5. Prevention advice: Tailored sun strategy and skin‑check schedule; signposting to lentigines, seborrhoeic keratosis and sun damage resources.

Reviewed by: Dr Mohammad Ghazavi, Consultant Dermatologist
Skinhorizon Clinic, 4 Clarendon Terrace, Maida Vale, London W9 1BZ
Last reviewed: 21 August 2025