Green nail syndrome

Overview

Green nail syndrome, also known as chloronychia, is a nail infection characterized by a greenish discoloration of the nail plate. It is most commonly caused by the bacterium Pseudomonas aeruginosa, which produces pigments that give the nail its distinctive green hue. The condition typically affects fingernails or toenails that are frequently exposed to moisture, chemicals, or minor trauma. While not usually serious, green nail syndrome can be persistent and cosmetically concerning, especially for individuals in occupations involving frequent hand immersion in water.

Causes

The primary cause of green nail syndrome is colonization or infection of the nail by Pseudomonas aeruginosa. This bacterium thrives in moist environments and can enter through breaks in the nail or surrounding skin. Risk factors include:

• Prolonged exposure to water: Common in dishwashers, healthcare workers, or swimmers

• Nail trauma: Lifting of the nail plate, cracks, or onycholysis (separation of the nail from the bed)

• Use of artificial nails: Acrylics or gels can trap moisture underneath

• Occlusive footwear: Promotes moisture retention in toenails

• Pre-existing nail disorders: Such as psoriasis or fungal infections

Symptoms

The hallmark symptom of green nail syndrome is discoloration of the nail. Key clinical features include:

• Greenish discoloration: Ranges from bluish-green to dark green, typically involving part or all of the nail

• Onycholysis: Separation of the nail from the nail bed, often starting at the distal end

• Mild tenderness or pain: Usually absent unless there is secondary inflammation or infection

• Occasional nail thickening or deformation: In chronic or repeated cases

There may be no systemic symptoms, and most cases are limited to cosmetic or local discomfort.

Diagnosis

Diagnosis of green nail syndrome is usually clinical but can be confirmed with laboratory tests in uncertain cases:

• Clinical inspection: Green discoloration with or without nail separation

• Nail culture: To identify Pseudomonas aeruginosa or rule out co-infection with fungi

• Wood’s lamp examination: May show fluorescence but is not specific

• KOH test or fungal culture: If concurrent fungal infection is suspected

Treatment

Treatment of green nail syndrome focuses on eliminating bacterial growth, reducing moisture, and restoring normal nail attachment. Options include:

Topical Treatments:

• Acetic acid soaks (vinegar and water): Helps acidify the environment and reduce bacterial growth

• Topical antibiotics: Such as gentamicin or ciprofloxacin solution applied directly to the affected nail

• Antiseptics: Like chlorhexidine or diluted bleach soaks in persistent cases

Systemic Antibiotics:

• Used in severe or resistant infections, typically oral fluoroquinolones such as ciprofloxacin

• Based on bacterial culture and sensitivity testing

Additional Measures:

• Keep nails clean and dry

• Trim and debride the affected nail

• Avoid occlusive gloves or shoes when possible

• Discontinue artificial nails until the infection resolves

Prognosis

The prognosis for green nail syndrome is generally excellent with appropriate treatment and moisture control. Most cases resolve within a few weeks to months. However, recurrence is common if underlying risk factors, such as chronic moisture exposure or nail trauma, are not addressed. In rare chronic cases, the nail may become permanently thickened or discolored. Preventive measures and proper hygiene are key to avoiding reinfection.