Onycholysis is a common condition where the nail plate separates from the nail bed. Nail plate separation can occur for various reasons, but the most common cause is onychomycosis (a fungal nail infection).1
Dermatologists often see 2 instances of onycholysis:2
Distal onycholysis: Nail plate separation beginning at the far edge of the nail and proceeding down toward the cuticle (most common).
Proximal onycholysis: The separation starts in the cuticle area and continues up the nail.
The separation of the nail from the nail bed can be a sign of many different nail traumas or conditions, including:
The space under your nails can be infected with yeast, which turns the loose portion of the nail a white or yellow tinge.1 A fungal infection requires further testing by a dermatologist to properly treat the condition. An untreated fungal infection can lead to pain, discomfort and even permanent disfigurement of the finger. However, the prescription medication required to treat fungal infections are expensive and can have side effects so be sure to discuss the pros and cons of treatment with your specialist.
Nail psoriasis can look very much like a fungal infection of the nail, making it difficult for your dermatologist to tell the 2 conditions apart unless a nail biopsy is performed. The most effective treatments for onycholysis caused by psoriasis are a class of medications called biologics—systemic medications that are most commonly administered by injection
Generally, if the infection under the nail appears to be green, a bacterial infection is to blame. One of the more common bacterial infections is pseudomonas, which is most often seen in people who frequently have their hands in water, such as waitresses, bartenders or nurses. Pseudomonas causes a blue-green or black discoloration on the nail plate and causes the nail plate to lift and separate from the nail bed. Treatment includes trimming away the separated nail, cleaning the nail bed, and applying a topical antibiotic.4 If the infection is severe, an oral antibiotic may be prescribed.
Trauma or Injury
Onycholysis usually occurs only in one nail when there is trauma or injury to a specific area and should heal on its own over time. There are a few different ways that the nails can sustain trauma or injury, such as:5
Long fingernails: Having long fingernails sometimes causes a nail to act as a lever, prying the nail away from the skin and preventing healing.
Local irritation: Local irritation can be from excessive filing of the nails, being overexposed to chemicals in manicures or nail tip application, allergic reactions to nail hardeners (from the formaldehyde found in trace amounts in nail polish and hardeners) or adhesives used to attach fake nails, or simply too much time spent with hands immersed in water.
Chemotherapy drugs can sometimes cause lifting of the nail plates. Also, individuals taking certain antibiotics (such a tetracycline) may be prone to a condition called photo-onycholysis if exposed to significant sunlight.6 The combination of the sun's UV rays and the antibiotic results in lifting of the nail plate. Other nonantibiotic medications can cause onycholysis of the fingers and toes without exposure to sunlight.
Iron Deficiency or Thyroid Over-Activity
In rare cases where all the nails are affected, onycholysis can be a sign of iron deficiency or thyroid over-activity. Increasing iron levels or treating hyperthyroidism may permit the nails to grow back normally.5
The presence of onycholysis for more than 6 months may lead to the permanent change of the structure of the nail bed, where the nail plate will no longer attach to the nail bed.
Surgical procedures performed in the nail bed (such as removal of a wart) can also result in permanent onycholysis because of permanent scar tissue that is formed. There is very little that can be done in this situation other than camouflaging the nail with polish.