Onycholysis refers to the progressive separation of the nail from its nail bed, the skin surface on which it rests. This condition, most often painless, affects both fingernails and toenails and can have a wide variety of causes. Understanding its origins allows for tailored treatment and helps prevent recurrence.
What is onycholysis?
Onycholysis is the partial or complete separation of the nail plate, the visible, hard part of the nail, from the nail bed beneath. This separation usually begins at the free edge of the nail, the white part that is typically trimmed, and can progress toward the base in more advanced cases. The detached area takes on a whitish or yellowish appearance because it is no longer supplied with blood by the underlying nail bed. In severe cases, the nail can detach completely. To understand why nails can also change in appearance for other reasons, our article on what your nails reveal about your health provides helpful insights.
What are the causes of onycholysis?
Onycholysis can result from very different causes, sometimes making it a complex diagnosis. Three main categories are distinguished. Mechanical causes are the most frequent: repeated trauma (wearing shoes that are too tight, intensive manual activities), overly aggressive cleaning under the nail, nail biting, or excessively forceful manicures. Prolonged contact with water also weakens the nail bed and promotes detachment. Dermatological causes include nail psoriasis, eczema, and other chronic inflammatory skin conditions. According to the French Society of Dermatology , psoriasis is responsible for approximately 30 to 50% of chronic onycholysis cases. Drug-induced or systemic causes are less well-known but important to identify. Certain antibiotics, particularly tetracyclines and fluoroquinolones, can cause photo-onycholysis when combined with sun exposure. Thyroid disorders, iron or zinc deficiencies, or fungal infections (onychomycosis) may also be the cause. 
What are the symptoms of onycholysis?
The main sign is visible nail detachment, which appears as a white or yellowish area extending from the free edge towards the lunula. The nail may also take on greenish or brownish hues if a bacterial superinfection develops in the detached area, creating a moist environment conducive to microorganisms. It is important to distinguish onycholysis from onychomycosis, a fungal infection of the nails, with which it is often confused. Onychomycosis is generally accompanied by nail thickening, more pronounced discoloration, and increased fragility with a tendency to crumble. Laboratory analysis is necessary to definitively differentiate between the two conditions.
How to treat onycholysis?
The treatment for onycholysis depends directly on its cause. There is no one-size-fits-all solution, and a dermatological consultation is recommended to establish an accurate diagnosis before initiating any treatment.
Treating the underlying cause
This is the essential starting point. If the onycholysis is related to psoriasis, appropriate dermatological treatment will be prescribed, often based on topical corticosteroids or biologic therapies in severe cases. If a fungal infection is confirmed, oral antifungal treatment is generally necessary for 6 to 24 weeks, as topical antifungals alone are rarely sufficient for deep-seated forms. If a drug-related cause is identified, stopping or replacing the offending medication, in consultation with the prescribing physician, may be enough to stabilize the onycholysis.
Local measures and nail protection
Regardless of the underlying treatment, certain local measures are always recommended. Detached nails should be trimmed short and regularly to avoid pulling, which worsens the detachment. Avoid picking at the area under the nail, as this could spread the detachment. Keeping the nails dry is essential: wearing gloves when working with water or household products significantly reduces moisture under the nail, a major aggravating factor.
Nutrition and dietary supplements
Certain nutritional deficiencies can weaken keratin and slow nail regrowth. Sufficient intake of iron, zinc, biotin , and sulfur-containing amino acids contributes to keratin quality. If a deficiency is confirmed by blood tests, targeted supplementation may be considered. Our article on how to treat damaged nails details nutritional approaches to strengthen nails.
How long does it take to heal from onycholysis?
Healing onycholysis requires the complete regrowth of a new, healthy nail, which takes between 4 and 6 months for fingernails and between 8 and 12 months for toenails. This timeframe explains why patience is essential and why it is important to treat the condition quickly to prevent further nail separation. Healing can be considered complete when the new nail, grown from the nail matrix, rests entirely on the nail bed without any areas of separation.
How to prevent onycholysis?
Prevention relies primarily on the daily mechanical and chemical protection of nails. Wearing gloves for housework and gardening, choosing properly fitting shoes to avoid repetitive trauma, trimming nails regularly, and avoiding overly aggressive manicures are the basic steps. Our article on natural remedies for brittle nails complements these tips with practical solutions. It is also important to avoid direct contact with chemicals, detergents, and solvents, which weaken the nail structure and nail bed. A balanced diet that provides the essential micronutrients needed for keratin synthesis also helps maintain strong nails in the long term.
Frequently asked questions about onycholysis
Is onycholysis contagious?
No. Onycholysis itself is not contagious because it is not an infection but a mechanical or inflammatory separation of the nail. However, if it is associated with onychomycosis, that is, a fungal infection, the latter can be transmitted through direct contact, particularly in swimming pools or changing rooms.
Can onycholysis be treated without going to the doctor?
In mild cases of mechanical origin, local protective and drying measures may be sufficient to stop the progression and allow regrowth. However, if onycholysis persists, spreads, or is accompanied by significant discoloration, a dermatological consultation is essential to rule out an infection or underlying disease.
Can onycholysis return after healing?
Yes, relapses are common if the underlying cause is not treated or if risk factors persist. In onycholysis related to psoriasis or chronic dermatosis, repeated episodes are possible despite proper treatment. Maintaining daily preventive measures remains the best long-term protection.
Does onycholysis affect women more than men?
Women are statistically more affected, primarily due to more frequent use of nail cosmetics (nail polish, artificial nails, nail polish remover) and regular manicures, which can weaken the nail bed. More frequent contact with water during household activities is another contributing factor.