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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:03/30/2017
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Patient Information for Pseudomonas nail infection - Nail and Distal Digit
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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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