Nail Disease – Specialist Diagnosis & Treatment of Nail Conditions in London

Understanding nail disease

Nail disease encompasses any condition that affects the nail unit. Because nails are slow-growing, changes often evolve over weeks to months, and a careful history plus targeted tests are essential to arrive at the correct diagnosis. Common categories include infections (fungal, bacterial or viral), inflammatory disorders (such as psoriasis and eczema), benign and malignant tumours (for example subungual warts, glomus tumours, squamous cell carcinoma or melanoma), traumatic and occupational nail problems, and nail changes due to systemic illness or drugs.

Patients typically present with one or more of the following: discolouration (yellow, brown, green or black), thickening or crumbling, splitting, pitting, ridges or grooves, lifting of the nail plate, painful swelling of the nail fold, or a visible mass beneath or beside the nail. Some patterns are highly suggestive of a particular diagnosis – for instance pitting points to nail psoriasis, while a green nail usually signals Pseudomonas bacterial colonisation.

Nail anatomy in brief

Understanding anatomy helps explain why nails behave the way they do:

• Nail matrix: The “factory” under the cuticle that makes the nail plate. Damage here leads to ridges, splitting or permanent deformity.
• Nail plate: The hard keratin structure you can see and trim.
• Nail bed: The tissue beneath the plate; disorders here cause onycholysis (lifting) or splinter haemorrhages.
• Proximal and lateral nail folds: Skin around the nail; inflammation causes paronychia (swelling, tenderness) and can distort growth.
• Hyponychium: The seal under the free edge; breaks allow infection in and irritants under the nail.

Causes of nail disease

Multiple processes can disturb the nail unit. The most frequent include:

• Fungal infection (onychomycosis): Thickened, crumbly, yellow or white nails; often associated with athlete’s foot. Toenails are more commonly affected than fingernails.
• Bacterial infection:
  • Acute paronychia (often Staphylococcus aureus): sudden painful swelling after a hangnail or manicure.
  • Chronic paronychia (mixed flora/yeast): persistent inflamed nail folds in wet‑work occupations.
  • Pseudomonas (“green nail”): decolouration under detached nail plates.
• Viral infection: Periungual warts (HPV) distort the nail edge and can be painful.
• Inflammatory skin disease:
  • Psoriasis: pitting, onycholysis, salmon patches (“oil drops”), subungual hyperkeratosis.
  • Eczema/dermatitis: ridging, brittleness, and swollen, tender nail folds.
  • Lichen planus: longitudinal ridging, thinning, dorsal pterygium (scarring).
• Trauma and mechanical causes: Repeated microtrauma in runners or tight footwear causes thick, bruised toenails; manicures or picking trigger habit‑tic deformity and median nail dystrophy.
• Tumours of the nail unit:
  • Benign: myxoid cysts, glomus tumour (cold‑sensitive pain), warts, onychomatricoma.
  • Malignant: squamous cell carcinoma of the nail bed; subungual melanoma (a widening, irregular dark band; pigment may extend onto surrounding skin – Hutchinson’s sign).
• Systemic disease associations:
  • Iron deficiency: brittle nails or koilonychia (spooning).
  • Thyroid disease: onycholysis and brittleness (hyperthyroidism classically).
  • Connective tissue disease: capillary changes and pits/ulcers at the nail folds in scleroderma or lupus.
  • Endocarditis/trauma: splinter haemorrhages.
  • Clubbing: bulbous fingertips with curved nails due to cardiopulmonary disease.
• Drug‑related changes: chemotherapy and antibiotics may cause melanonychia (brown/black bands), Beau’s lines (transverse grooves), or onycholysis (e.g., doxycycline + sun).

Symptoms and patterns to look for

• Colour: yellow (fungus), green (Pseudomonas), brown/black (melanin, blood or dirt), white patches (leukonychia), blue/black (subungual haematoma).
• Surface/texture: pitting, roughness, longitudinal ridges, “sandpaper” nails.
• Shape: spooning (koilonychia), clubbing, scarring with pterygium formation.
• Attachment: onycholysis (lifting) with a white/yellow gap; often sensitive to water/chemicals.
• Skin around the nail: red, swollen nail folds (paronychia), tender granulation tissue in ingrown toenails.
• Pain: consider acute infection, glomus tumour, ingrown nail, or subungual haematoma.

Diagnosis

Because many nail problems look alike, a structured approach prevents misdiagnosis:

• History: onset and timeline, occupation and hobbies, footwear, salon treatments, trauma, medical conditions, and medications.
• Clinical examination: onychoscopy (dermoscopy for nails) helps differentiate pigment types and assess structures like the matrix and hyponychium.
• Laboratory tests:
  • Mycology: nail clippings/scrapings for microscopy and culture or PAS stain to confirm fungus before oral therapy.
  • Bacterial culture: in persistent paronychia or green nails.
  • Blood tests: if systemic disease suspected (iron, thyroid, autoimmune markers).
• Imaging: ultrasound or MRI for suspected glomus tumour or deep mass; X‑ray if bone involvement.
• Biopsy: matrix or bed biopsy when a tumour, lichen planus or unusual inflammatory disease is suspected. Suspicious melanonychia usually requires a matrix biopsy to exclude subungual melanoma.

Treatment and management

Effective care targets the underlying cause and supports healthy regrowth:

• Fungal infection:
  • Topicals (amorolfine, ciclopirox) for mild/distal disease; require months of use as the nail grows out.
  • Oral antifungals (terbinafine, itraconazole) for extensive or matrix involvement; baseline liver checks may be needed.
  • Adjuncts: regular debridement, keeping feet dry, treating tinea pedis, disinfecting footwear.
• Bacterial/paronychia: warm soaks, topical or oral antibiotics ± drainage of abscess; for chronic paronychia, reduce wet work, use emollients and topical steroids/antifungals.
• Psoriasis and eczema: potent topical steroids or vitamin D analogues under the proximal fold; intralesional steroid injections for resistant matrix disease; systemic/biologic therapy if severe skin/joint disease coexists.
• Lichen planus: intralesional/topical steroids, short courses of systemic therapy in scarring cases.
• Trauma/ingrown nails: footwear modification, nail bracing/taping, partial avulsion with phenolisation for recurrent ingrown toenails.
• Benign tumours and cysts: aspiration or surgical excision; laser options for warts.
• Malignancy: urgent surgical excision with appropriate margins; melanoma and SCC require specialist oncology input and staging.
• Drug‑related change: review necessity, consider alternatives, sun protection, and protective nail care.

Evidence‑based nail care and prevention

• Keep nails short and squared at the corners to reduce ingrowing.
• Do not cut or aggressively push back cuticles; they form a protective seal.
• Use non‑acetone removers and limit gel/acrylic cycles; allow “nail holidays.”
• Moisturise nails and surrounding skin with bland emollients; consider urea‑containing creams for thick toenails.
• For wet‑work jobs, wear cotton liners under waterproof gloves and take glove breaks.
• Choose wide toe‑box footwear and moisture‑wicking socks; disinfect shoes if fungal infection is present.
• In salons, ensure instrument sterilisation and avoid cutting living tissue.

Special groups

• Children: many nail changes are benign (e.g., leukonychia, mild ridging). Persistent warts or painful ingrown nails warrant care.
• Pregnancy: pigment bands may appear; many medicines (e.g., oral antifungals) are avoided—seek specialist advice.
• Athletes/runners: repetitive trauma causes subungual haematoma and thick nails; footwear and nail‑length optimisation help.
• Diabetes/poor circulation: higher risk of infection, ulceration and slow healing—prompt podiatry/dermatology input recommended.
• Immunosuppressed patients: atypical, extensive infections and tumours occur more frequently; lower threshold for biopsy and systemic therapy.

When to seek urgent assessment

• A new or changing dark band on a single nail, especially if widening, irregular or accompanied by pigment on adjacent skin (Hutchinson’s sign).
• Rapidly enlarging mass, persistent bleeding or ulcer under a nail.
• Severe pain or spreading redness/swelling (possible abscess).
• Non‑healing trauma or recurrent ingrown toenails despite good care.
• Nail changes with systemic symptoms (breathlessness, fever, weight loss) or new digital clubbing.

Prognosis and expectations

Most nail diseases improve with accurate diagnosis and consistent treatment, but patience is essential: fingernails take 4–6 months to grow out; toenails may need 9–12 months. Recurrence can happen if triggers persist (e.g., sweaty footwear, wet work, psoriasis flares). Regular follow‑up allows treatment to be fine‑tuned and prevents avoidable complications.

Services at Skinhorizon Dermatology London

• Onychoscopy and expert clinical assessment.
• Mycology (microscopy, culture, PAS), bacterial culture where indicated.
• Matrix/bed biopsy for suspicious lesions or scarring disorders.
• Procedures: partial avulsion/phenolisation, debridement, intralesional steroid injections, wart therapies, cyst excision.
• Integrated care with podiatry and oncology where required.

Your first visit — what to expect

1. History: Onset, symptoms, prior treatments, medical conditions and lifestyle factors.
2. Examination: Detailed nail and skin assessment with onychoscopy.
3. Investigations: Clippings/scrapings for mycology, cultures, blood tests or imaging; biopsy if needed.
4. Management plan: Cause‑led treatment, nail‑care routine, footwear and workplace advice.
5. Follow‑up: Review at appropriate intervals to monitor regrowth and adjust therapy.

Reviewed by: Dr Mohammad Ghazavi, Consultant Dermatologist
Skinhorizon Clinic, 4 Clarendon Terrace, Maida Vale, London W9 1BZ
Last reviewed: 22 August 2025