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Pseudomonas nail infection - Nail and Distal Digit
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Pseudomonas nail infection - Nail and Distal Digit

Contributors: Shari Lipner MD, PhD, Susan Burgin MD, Bertrand Richert MD, Robert Baran MD
Other Resources UpToDate PubMed


The "green nail syndrome," or chloronychia, is characterized by the clinical triad of:
  • Green discoloration of the nail plate
  • Paronychia
  • Distolateral onycholysis
Pseudomonas species are gram-negative, aerobic coccobacilli that are found in soil, water, plants, and animals (including humans). Pseudomonas aeruginosa is an opportunistic pathogen that can infect pulmonary, kidney, and urinary tract systems. It may infect soft tissue, skin, and nails in both immunocompetent and immunocompromised patients. The bacteria can colonize and infect any area of the nail plate (distal, lateral, proximal) where there is onycholysis. Exposure to a moist environment or frequent use of soaps / detergents, trauma, onychotillomania (compulsive manipulation or pulling out of the nails), chronic paronychia, and associated nail diseases such as psoriasis may promote infection by Pseudomonas. The subsequent pigmentation varies both with the species involved and with the composition of the pigments produced. The greenish hue varies from light green to deep, dark green. Pseudomonas species produce a number of diffusible pigments such as pyocyanin (dark green) and fluorescein (yellow-green). Both are soluble in water; the former is also soluble in chloroform.

The main complaint of patients is the green discoloration of the nails. Patients must avoid excessive exposure to moist environments, or they will have a high rate of recolonization even after treatment.

Green nails are more common in hairdressers, dishwashers, food handlers, and health care workers.

Green nail syndrome is rare in children but can be seen in those who are immunosuppressed.


A49.8 – Other bacterial infections of unspecified site

402932005 – Pseudomonas aeruginosa infection of nail

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Last Reviewed:03/05/2017
Last Updated:02/14/2022
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Patient Information for Pseudomonas nail infection - Nail and Distal Digit
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Contributors: Medical staff writer


Pseudomonas is a common bacteria that likes moist places. These germs can infect any place of your body that is often wet, such as your ears or your fingernails. Nail infection is usually caused by frequently exposing your hands to moisture. Previous injury to a nail, or another nail disease such as psoriasis, may make you more likely to have Pseudomonas nail infection.

This infection can occur on your hands or feet. It may only affect 1 or 2 nails, or it may be more widespread.

Pseudomonas nail infection is also called green nail syndrome because of the green discoloration caused by the bacteria.

Who’s At Risk

You're at risk of developing Pseudomonas nail infection if your hands or feet are constantly exposed to moisture, or if you frequently use soaps / detergents.

Immunocompromised and elderly individuals are more likely to get Pseudomonas nail infection. It is rare in children.

Signs & Symptoms

Infected nails may be green-black or green-blue. The skin around the nail may be swollen, and the nail may also lift off from your finger or toe.

Self-Care Guidelines

Soaking the affected fingers in a vinegar solution may help treat the infection. Dilute 1 part vinegar with 5 parts water and soak for an hour. This can be done twice a day.

To help prevent future infections:
  • Wear gloves to shield your hands from water and chemicals.
  • Keep nails trimmed as short as possible.

When to Seek Medical Care

Contact your doctor if one or more of your nails turns a green color, or your nail is lifting from the nail bed.


Your doctor may prescribe a topical antibiotic you can apply under the edge of the affected nails.

If those measures are ineffective, oral antibiotics may be prescribed to kill the infection.
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Pseudomonas nail infection - Nail and Distal Digit
A medical illustration showing key findings of Pseudomonas nail infection : Diffuse green nails, Scattered nails or distal digits, Onycholysis
Clinical image of Pseudomonas nail infection - imageId=967363. Click to open in gallery.  caption: 'Deep greenish-black discoloration of an onycholytic nail (represented by the adjacent yellowish nail discoloration).'
Deep greenish-black discoloration of an onycholytic nail (represented by the adjacent yellowish nail discoloration).
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