Lichen Planus Affecting the Nails: Signs, Risks and Professional Considerations

What Is Lichen Planus?

Lichen planus is a chronic inflammatory condition of unknown precise cause, thought to involve an abnormal immune response against the body’s own epithelial cells. It most commonly affects the skin — where it presents as itchy, flat-topped, violaceous (purplish) papules — and the mucous membranes of the mouth and genitals. Nail involvement occurs in an estimated 10% of people with lichen planus, though the nails may be the only site affected in some individuals.

The condition can affect any nail, and may affect multiple nails simultaneously. It is not contagious. The cause of nail involvement is direct inflammatory attack on the nail matrix — the structure responsible for producing the nail plate — which is why the resulting nail changes are structural rather than superficial.

How Lichen Planus Affects the Nails

Because lichen planus targets the nail matrix, its primary effects are seen in the nail plate structure — the output of the matrix. The nail bed can also be involved, adding further signs to the clinical picture.

Longitudinal ridging and furrowing

Ridges running the length of the nail — longitudinally — are among the earliest and most characteristic signs of nail lichen planus. In early stages, the ridging may be subtle, resembling normal ageing changes in the nail plate. As the condition progresses, the ridges deepen and multiply, giving the nail plate a corrugated or channelled appearance.

Nail plate thinning

The inflammatory damage to the matrix reduces its capacity to produce a full-thickness nail plate, causing the plate to become progressively thinner. A thinned plate is fragile and prone to splitting, crumbling at the free edge, and breaking under normal daily use.

Onycholysis

Separation of the nail plate from the nail bed — onycholysis — can occur in nail lichen planus as a result of bed involvement by the inflammatory process. The onycholysis in this context is driven by the condition itself rather than by external mechanical factors and will not resolve without treatment of the underlying condition.

Pterygium unguis

Pterygium unguis — the forward migration of the proximal nail fold skin onto the nail plate surface — is a hallmark sign of nail lichen planus and indicates significant scarring of the matrix beneath. The skin creeps forward to fill the space where the nail plate has been lost or destroyed. This is an irreversible change: where pterygium has formed, the nail plate will not regrow. The extent of pterygium formation reflects the extent of permanent matrix damage.

Twenty-nail dystrophy

When all twenty nails are affected — showing uniform roughness, longitudinal ridging, and brittleness — this presentation is known as twenty-nail dystrophy or trachyonychia. While twenty-nail dystrophy has multiple possible causes, lichen planus is one of the most significant among them. The nails appear sandpaper-like in texture and dull in appearance.

The Risk of Permanent Nail Damage

Unlike many nail conditions, lichen planus carries a genuine risk of permanent, irreversible nail loss if left untreated or if treatment is delayed. The inflammatory process directly attacks the nail matrix, causing progressive scarring. Once the matrix is scarred, it cannot regenerate — meaning the nail plate it would have produced is permanently lost.

The severity of outcome varies considerably between individuals. Some people experience mild nail changes that stabilise with treatment. Others experience progressive scarring and partial or complete permanent nail loss on affected digits. Outcomes are generally better when treatment is initiated early, before significant scarring has occurred.

Professional Considerations in the Salon

Fragility requires adapted technique

Nails affected by lichen planus are structurally fragile — thinned, ridged, and prone to splitting. Any mechanical work on or around these nails must be extremely gentle. Aggressive filing, buffing, or cuticle work risks causing further damage to an already-compromised nail plate and the structures beneath it.

Trauma risk and the nail matrix

Because the nail matrix is the primary site of damage in lichen planus, any trauma to the proximal nail area — including the eponychium and proximal fold — carries additional risk. Cuticle work in this zone should be minimal and non-invasive. E-file work near the proximal fold is contraindicated in active disease.

Product application considerations

Whether nail products can be applied to nails affected by lichen planus depends on the individual nail condition. A thinned, fragile nail plate may not provide adequate support for enhancements. Where onycholysis is present, product must not be applied over the separated zone. Colour cosmetic products — gel polish or standard polish — may be appropriate on minimally affected nails, with the caveat that removal must be gentle.

Always obtain informed consent from the client and document the nail condition and any adaptations made before proceeding.

Pterygium — do not attempt removal

Pterygium unguis attached to the nail plate should never be manipulated, lifted, or attempted to be pushed back in the salon. The skin has adhered to the plate due to scarring beneath, and any attempt to separate it risks bleeding, pain, and further trauma to an already-damaged area. This is a clinical finding that requires medical management only.

When to Refer

Given the risk of permanent nail loss, the threshold for referral in potential nail lichen planus should be low. Refer promptly when:

• A client presents with progressive nail thinning, deepening longitudinal ridges, or fragility without a clear mechanical cause
• Pterygium unguis is observed — the forward migration of proximal fold skin onto the nail plate
• Multiple nails are affected simultaneously with similar changes
• The client reports that nails are progressively worsening
• All twenty nails show trachyonychia-type changes (rough, ridged, sandpaper texture)
• Any suspected nail lichen planus without confirmed diagnosis — early dermatological assessment is essential given the irreversibility of late-stage changes

Common Misconceptions

Lichen Planus vs Fungal Infection — Recognising the Difference

One of the most common errors in professional nail assessment is mistaking subungual changes — whether from lichen planus, nail psoriasis, or other conditions — for a fungal nail infection. Subungual hyperkeratosis — the build-up of keratinous debris beneath the nail plate that occurs in lichen planus — can look visually similar to fungal disease. The cause, the behaviour, and the professional decisions that follow are entirely different.

This distinction matters because fungal infection is contagious — it requires refusal of service, referral, and strict hygiene management. Lichen planus is not infectious — it is an autoimmune inflammatory condition. Treating the two the same way leads to either refusing service unnecessarily or, far more dangerously, applying product over an active infection and spreading it through tools to other clients.

The mistake that causes most harm

The most common incorrect assumption is that anything found beneath the nail plate — debris, scale, discolouration — is either product lifting, dirt, or something that can be cleaned out and worked over. This thinking leads directly to two categories of serious error: applying product over an active fungal infection, and using tools on infected nails that then contact other clients without adequate sterilisation.

Recognising that subungual changes have different causes — and that some are not infectious while others are — is not an advanced skill reserved for medical professionals. It is a foundational part of professional nail assessment. A nail technician does not need to diagnose the specific condition. They do need to recognise that something is present that requires assessment before any service decision is made.

Frequently Asked Questions