The Bottom Line

Onycholysis means your nail is painlessly separating from the skin underneath it (the nail bed), creating a white or yellowish gap that grows from the tip toward the cuticle. It is one of the most common nail complaints, affecting up to 5% of the population at any given time. The most important thing to know: clipping back the lifted nail and keeping it dry is the cornerstone of treatment, and the underlying cause must be identified — because onycholysis can signal psoriasis, thyroid disease, or a fungal infection that needs specific treatment.

What Is Onycholysis?

The word comes from Greek: onyx (nail) and lysis (loosening). When the nail lifts away from the nail bed, air or debris fills the gap, making the nail look white, yellow, green, or even brownish, depending on what is in the space. The nail itself is not crumbling or thickening — it is simply detached, like a label peeling off a bottle.

Onycholysis most commonly affects fingernails (particularly the ring finger and index finger) and can involve one nail or many. It is usually painless, but the lifted nail is fragile and can catch on clothing or be accidentally torn, which is painful.

The condition is twice as common in women as in men, likely because of greater exposure to prolonged wet work, nail cosmetics, and nail trauma from longer nail length.

What Does It Look Like?

The classic appearance is a pale or whitish crescent-shaped area at the free edge of the nail that extends back toward the cuticle. The boundary between attached and detached nail is often sharp and clearly visible. In some cases:

  • A green or black discoloration develops under the nail, indicating secondary infection with Pseudomonas aeruginosa bacteria — which thrives in the dark, moist space
  • Yellow-brown discoloration can suggest fungal infection (onychomycosis) co-existing with the separation
  • Oil-drop discoloration — a translucent salmon-pink area — behind the detached zone is a hallmark of psoriatic onycholysis
  • The nail may also show pitting (small ice pick-like depressions) if psoriasis is the underlying cause

What Causes Onycholysis?

Identifying the cause is the most important step, because the treatment depends on it. Causes fall into several categories:

Trauma (Most Common)

Repeated minor trauma is the leading cause overall — particularly in people with long nails who type heavily, play guitar, or do work that presses the nail tip repeatedly. A single acute injury (slamming a finger in a door) can also cause separation that persists for months while the nail regrows.

Skin Conditions

  • Psoriasis: Nail involvement occurs in 50% of psoriasis patients and up to 80% of those with psoriatic arthritis. Psoriatic onycholysis has the characteristic oil-drop sign
  • Contact dermatitis: Allergic reaction to nail polish, acrylic nails, or cleaning products can inflame the nail bed and cause separation
  • Eczema: Chronic inflammation around the nail fold can affect attachment

Fungal Infection (Onychomycosis)

Dermatophyte fungi can invade the nail bed from the free edge, causing lifting as the infection progresses. This is distinguished from other causes by a KOH preparation or fungal culture of nail scrapings.

Systemic Diseases

  • Thyroid disease: Both hyperthyroidism and hypothyroidism can cause nail changes. Hyperthyroid onycholysis (Plummer's nails) specifically affects the ring and little fingers, with a characteristic distal curved border
  • Iron deficiency anemia
  • Pregnancy
  • Diabetes mellitus
  • Peripheral vascular disease

Medications

Drug-induced photo-onycholysis is a well-recognized reaction in which sunlight activates a drug deposited in the nail bed, causing it to lift. Common culprits include tetracycline antibiotics (especially doxycycline), fluoroquinolones, psoralens, and taxane chemotherapy agents (which cause onycholysis in up to 40% of patients receiving paclitaxel).

Wet Work and Chemical Exposure

People who repeatedly immerse their hands in water — dishwashers, nurses, swimmers — are at higher risk because prolonged moisture softens the nail's attachment to the bed.

Treatment

Treatment targets both the cause and the detached nail itself.

Step 1: Clip Back the Detached Nail

This is the single most important step. The detached nail cannot reattach — it must regrow from the matrix. Leaving it in place traps moisture and debris, encouraging secondary infection. Clip the lifted nail as far back as it is separated, then keep the area clean and dry.

Step 2: Keep It Dry

Moisture prolongs the condition. Wear waterproof gloves when doing dishes or wet work. Avoid soaking nails in water. Let nails air-dry fully after washing. Remove nail polish and artificial nails to allow the nail bed to breathe.

Step 3: Treat the Underlying Cause

  • Fungal infection: Topical antifungals (ciclopirox, efinaconazole) or oral antifungals (terbinafine, itraconazole) depending on severity
  • Psoriasis: Topical steroids under the nail, intralesional injections, or systemic biologic therapy for widespread disease
  • Contact allergy: Identify and avoid the offending product; patch testing by a dermatologist can pinpoint the allergen
  • Thyroid disease: Referral to endocrinology; treating the thyroid condition often resolves the nail changes
  • Drug-induced: Stopping or changing the offending medication if possible; wearing UV-protective gloves in sunlight if the medication cannot be stopped

Treating Pseudomonas Infection

Green discoloration under a lifted nail means Pseudomonas bacteria are growing there. Treatment involves soaking the nail in dilute acetic acid (white vinegar) for 10-15 minutes twice daily. Topical ciprofloxacin or gentamicin drops can also be used. The green color fades as treatment works.

How Long Until the Nail Heals?

Fingernails grow approximately 3 mm per month and take 4-6 months to fully replace themselves. Toenails take 12-18 months. Onycholysis will resolve only when new nail grows out from the matrix — so even after the cause is corrected, patience is needed.

When to See a Dermatologist

  • Nail separation is spreading or affecting multiple nails
  • You see green, black, or unusual discoloration under the nail
  • You have psoriasis and nail changes are worsening or causing pain
  • Home care with clipping and drying has not improved the nail after 2-3 months
  • You are taking a medication that may be causing photo-onycholysis
  • You have unexplained nail changes with symptoms of thyroid disease (fatigue, weight changes, heart palpitations)

Frequently Asked Questions

Can onycholysis be cured?

Yes, in most cases. If the cause is identified and treated, and the nail is kept dry and clipped back, the nail bed reattaches to the new nail as it grows in. Recovery is slow (months) but complete in most people.

Is onycholysis contagious?

Onycholysis itself is not contagious. If a fungal infection is the cause, the fungus can spread to other nails or to other people through shared surfaces — but the separation itself is a symptom, not an infectious disease.

Can I wear nail polish with onycholysis?

It is generally best to avoid nail polish, gel, and acrylic nails during treatment. These products trap moisture, can worsen separation, and may themselves be an allergen. Once the nail has fully healed, you can return to nail cosmetics, though regular breaks are a good idea.

My nail turned green — is that serious?

Green discoloration under a lifted nail is caused by Pseudomonas bacteria and should be treated. It is not dangerous or deeply invasive, but it will not go away on its own. Vinegar soaks and sometimes antibiotic drops are needed. See a dermatologist if it does not respond within 4-6 weeks.

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  3. Rich P. Nail disorders: diagnosis and treatment of infectious, inflammatory, and neoplastic nail conditions. Med Clin North Am. 1998;82(5):1171-1183.
  4. Baran R, Dawber RPR, de Berker DAR, et al. Baran and Dawber's Diseases of the Nails and Their Management. 4th ed. Wiley-Blackwell; 2012.

Trusted Resources

Always consult a board-certified dermatologist for an accurate diagnosis and personalized treatment plan. This article is for educational purposes only and does not replace professional medical advice.