A green spot on a fingernail or toenail can be concerning, but this discoloration is a common occurrence. Understanding its cause can help address the issue.
Understanding the Green Discoloration
The green discoloration on a nail can vary in shade, ranging from a light, yellowish-green to a dark green or even a brownish-green hue. This altered color typically appears under the nail plate, often in areas where the nail may have lifted slightly from its bed. This specific condition is medically recognized by the term “chloronychia.”
The distinctive green color associated with chloronychia is not a stain from an external source but rather a pigment produced within the nail unit itself. This pigment is a byproduct of certain microorganisms thriving in the nail environment. The presence of these organisms indicates a localized infection, which leads to the visible change in nail color.
The Primary Culprit
The most frequent cause behind green nail discoloration is a bacterium known as Pseudomonas aeruginosa. This bacterium is widespread in the environment and thrives particularly well in moist conditions. Areas under the nail, especially if there is a gap between the nail plate and the nail bed (a condition called onycholysis), provide an ideal breeding ground for these microorganisms.
Factors that contribute to the growth of Pseudomonas aeruginosa include prolonged exposure to water, such as frequent dishwashing without gloves, or activities that keep hands or feet wet for extended periods. The presence of artificial nails or nail polish can also trap moisture underneath, creating a favorable environment for bacterial proliferation. Even minor trauma to the nail or underlying fungal infections can create tiny spaces where these bacteria can colonize and multiply.
The characteristic green color results from specific pigments produced by Pseudomonas aeruginosa. These pigments, primarily pyocyanin and pyoverdin, are secreted by the bacteria as they grow. Pyocyanin often imparts a blue-green color, while pyoverdin contributes a yellow-green shade, and their combination creates the spectrum of green observed in affected nails. The accumulation of these pigments under the nail plate is what becomes visible as the green spot.
When to Consult a Professional
While a green nail is often a common bacterial infection, professional medical advice is necessary if the discoloration persists or worsens. Consult a healthcare provider if you experience additional symptoms.
Concerning symptoms include pain, tenderness, swelling, redness, or pus drainage around the nail. Seek prompt medical attention if the discoloration spreads to other nails or increases in size. A healthcare provider can diagnose the issue, rule out other conditions, and recommend treatment.
Care and Prevention
Preventing green nail discoloration involves careful nail hygiene. Keep nails clean and dry, as moisture allows bacteria to flourish. Thoroughly dry nails and surrounding skin after washing or bathing, and avoid prolonged water immersion.
Regular and proper nail care is also beneficial. Trim nails straight across and file the edges gently to prevent ingrown nails or trauma that could lift the nail plate. Avoid using sharp instruments to clean under the nails, as this can create microscopic openings for bacteria. Instead, a soft brush can be used to gently clean the underside.
For tasks that involve extended water exposure, such as cleaning or dishwashing, wearing protective gloves can significantly reduce the risk. If toenails are affected, ensure footwear is not too tight and allows for adequate air circulation. Addressing any underlying conditions, such as existing fungal infections of the nail, is also important. Fungal infections can damage the nail, making it more susceptible to bacterial colonization and green discoloration.