Green-black discolouration under a lifted nail before a gel manicure
Mrs Okafor, 61, books a gel manicure before her daughter's graduation on Saturday. On examination, the nail plate of her right middle finger is lifted at the free edge, and there is a dark green-black discolouration under the lifted portion with a faint musty smell. The surrounding nail fold is not hot, red or swollen and she has no pain. She has worn gel polish continuously for eight months; the green appeared about three weeks after her last set was removed at another salon, where the nail was filed 'quite hard'. She has type 2 diabetes controlled with metformin (last HbA1c 7.1%) and no neuropathy. She wants the gel reapplied because 'it's only a bit of discolouration', and she flies for six weeks on Sunday. She asks whether you can buff the green off and carry on. The other nine nails are healthy.
1. What do you suspect is happening to the nail, and can you apply the gel polish as requested?
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Suspicion: bacterial colonisation of the nail bed by Pseudomonas aeruginosa following onycholysis. The separation was probably caused by over-filing and repeated gel application and removal; moisture then collects under the lifted plate, and the green-black colour is pyocyanin pigment produced by the bacteria, which also explains the musty smell. The absence of heat, redness, swelling and pain suggests it is currently localised rather than a spreading infection - but it is still an active infection risk and a contraindication to enhancement.
Do not apply gel to that nail. Reasons:
- An enhancement seals the plate, trapping warmth and moisture and feeding the bacteria.
- Buffing will not remove the colour, because the pigment lies in the nail plate and bed, not on the surface. Aggressive buffing thins the plate further, increases separation and raises the risk of the infection spreading.
- Her diabetes means slower healing and greater vulnerability to infection, even when well controlled, so any break in the skin or nail unit deserves extra caution.
What to do instead: decline the enhancement on that nail, do not probe or scrape under the plate, explain what you can see and why you are stopping, and refer her to her GP (or a podiatrist, given her diabetes) for assessment and treatment. You may manicure the other nine nails only if she wants that and you can maintain strict hygiene: separate tools, no shared files, single-use abrasives, thorough disinfection of reusable metal implements. Avoid aggressive cuticle work and any nicks.
2. How would you distinguish this from a subungual haematoma and a subungual melanoma, and why does it matter?
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The differences matter because the referral urgency and your treatment decision are completely different.
- Subungual haematoma. There is a clear history of trauma (door, heavy object, sports), often with initial pain; the colour is red-purple to black, the stain grows out distally with the nail plate, and there is no smell or green tint. Unless trauma also caused the lifting, the plate is not separated.
- Subungual melanoma. Typically a longitudinal brown-black band on a single digit, often widening over time; pigment may spread onto the nail fold or cuticle (Hutchinson's sign). There may be no trauma, no odour and no link to polish, and the nail may become dystrophic. This needs urgent dermatological referral.
- Fungal infection. Yellow-white, thickened and crumbly rather than green-black, often several nails, confirmed by laboratory testing.
Mrs Okafor's picture - visible onycholysis, green-black colour confined to the lifted area, musty smell and a clear history of hard filing and continuous polish - fits Pseudomonas best. If any feature does not fit, or the discolouration is a band, extends to the cuticle or persists after the lifting resolves, refer on the basis of uncertainty. Never buff or cover pigment to 'tidy it up', because that can delay a diagnosis.
3. What advice, aftercare and infection-control measures should accompany this client's visit, and what do you record?
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Advice to the client.
- Keep the nail short, clean and dry; dry thoroughly after washing and avoid prolonged soaking.
- Leave it uncovered - no polish or gel - and do not pick at or push under the lifted plate, so it can reattach as it grows out.
- Do not share clippers or files with family.
- See her GP or podiatrist promptly, and tell them she has diabetes.
- Return for review only when the infection has cleared and the nail has grown out; if the area becomes painful, hot, red or swollen, or she feels unwell, seek medical advice urgently.
- Daily foot checks are good practice given her diabetes.
Infection control in the salon. Treat her as a potential cross-infection risk without stigmatising her: hand hygiene before and after; single-use files and buffers discarded in the clinical waste; metal tools cleaned then disinfected with a hospital-grade virucidal/bactericidal agent or autoclaved where possible; work surfaces and lamps wiped; no double-dipping; keep the affected hand's tools separate from those used on her other nails.
Record the nail, digit and size, the colour and lifting, the smell, the absence of inflammation, what she reported about the previous salon, the service declined and why, the referral made, the advice given, the treatment actually carried out, and her signed acknowledgement. Record facts, not a diagnosis - write 'suspected bacterial infection, referred'.