Health condition
Twenty-nail dystrophy
Twenty-nail dystrophy (trachyonychia) is a benign condition in which some or all nails become rough, ridged and sandpaper-like; in children it often resolves on its own, and in all ages it matters mainly for what it is sometimes associated with - alopecia areata, lichen planus, psoriasis or eczema.
Why trust this guide
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Editorial team
Written by our editorial team from the UK sources listed on each page.
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Sourced from guidance
Checked against current NHS and UK specialist society guidance at the time of review.
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Current for 2026
Reviewed on 2026-09-27 with the next review scheduled for 2027-09-27.
Key facts
The essentials at a glance.
The symptoms to recognise, when to seek help, which specialist to see, and what treatment usually involves.
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Nails develop fine longitudinal ridging, roughness and a dull sandpaper texture ("opaque type"), or shiny pitted change - despite the name, not all twenty nails need be involved
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It is a reaction pattern, not a single disease: associations include alopecia areata (the commonest), lichen planus, psoriasis and atopic eczema; many cases are idiopathic
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It is not fungal - and clippings for mycology are worthwhile to prove it before any antifungal is considered
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Childhood cases usually improve spontaneously over several years; treatment options for troublesome disease include topical or intralesional steroids and oral therapy chosen by association
Understanding the condition
What it is and what happens next.
What causes it, how it is diagnosed, and the treatment routes available in the UK.
What it is and how it feels
Trachyonychia arises when inflammation - of several possible kinds - disturbs the nail matrix, the factory under the cuticle, so the plates emerge with surface texture rather than gloss. The change is symmetrical, gradual and usually painless; the practical impacts are cosmetic, snagging on fabrics, and the anxiety of watching every nail change without knowing why.
Diagnosis and treatment routes
A dermatologist examines skin, scalp and mouth for the associated conditions, sends clippings to exclude fungus, and only rarely needs a nail matrix biopsy; when alopecia areata or lichen planus is found elsewhere, the nail findings usually need no separate proof. Since spontaneous improvement is common - the norm in children - watchful waiting with nail care advice (short nails, moisturised cuticles, avoiding trauma and harsh cosmetics) is legitimate first-line management, with steroid-based treatment reserved for significant symptomatic or occupational impact. In much of the UK, a routine NHS referral to the relevant specialist clinic can take several months, whereas an initial appointment with a private consultant is typically available within around two weeks.
Seeing a specialist
Who to see, and how quickly you can be seen.
The specialist for this condition is usually a consultant dermatologist. Your GP can refer you on the NHS, or you can arrange a private consultation directly.
A quiet reminder
This guide is for information, not medical advice.
Your GP knows your history and can tell you which parts apply to you. If in doubt, see them - and seek urgent care for any of the emergency symptoms described above.
Frequently asked
Common questions about Twenty-nail dystrophy.
Quick, plain-English answers to what people ask us most.
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What is twenty-nail dystrophy?
It is a condition causing abnormal changes, such as ridging, roughness or thinning, affecting all twenty fingernails and toenails.
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What causes twenty-nail dystrophy?
It is most often associated with lichen planus, alopecia areata, psoriasis, or eczema affecting the nail matrix, though in some cases, particularly in children, no clear underlying cause is found (idiopathic).
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What does twenty-nail dystrophy look like?
Nails typically appear rough, ridged, thin, or brittle, sometimes with a sandpaper-like texture, affecting all nails to some degree rather than just one or two.
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Is twenty-nail dystrophy dangerous?
It is not dangerous or a sign of serious internal disease on its own, though it's worth checking for an associated skin condition, as treating that can improve the nail changes.
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Is twenty-nail dystrophy genetic?
It is not typically inherited itself, though some of the associated conditions, such as psoriasis, can have a genetic predisposition.
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Can twenty-nail dystrophy be treated?
Treatment focuses on managing any underlying condition (such as lichen planus or alopecia areata); topical or, occasionally, injected steroids can help, though improvement can be gradual and some cases, particularly idiopathic ones in children, resolve on their own over time.
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How is twenty-nail dystrophy diagnosed?
Diagnosis is usually made by clinical examination, sometimes supported by a nail biopsy if the underlying cause isn't clear or if lichen planus is suspected.
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How long does it take to improve?
Idiopathic cases in children often improve spontaneously over a few years, while cases linked to an underlying condition improve at a pace depending on how well that condition responds to treatment.
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Twenty-nail dystrophy vs fungal nail infection - what's the difference?
Twenty-nail dystrophy affects all nails fairly uniformly and is linked to an underlying skin condition, while fungal infection often starts in one or a few nails and progresses unevenly, with a different appearance (yellowing, thickening) confirmed by nail sampling.
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When should I see a dermatologist about nail changes, and how quickly can I be seen privately?
See a dermatologist if all your nails are affected or changes persist. NHS dermatology waits can be 20-45+ weeks; private dermatologists can often see you within about two weeks.