Medical Causes of Green Skin Discoloration
Green skin is not a normal human condition and is almost always a sign of an underlying medical issue, though many are very rare. The key to understanding the cause lies in identifying whether the discoloration is localized or widespread.
Biliverdin and Obstructive Jaundice
One of the most clinically significant causes of a green tint to the skin is related to liver dysfunction. Jaundice is a condition where the skin and whites of the eyes turn yellow due to a buildup of bilirubin, a yellowish waste product of red blood cell breakdown. In severe or chronic cases of obstructive jaundice, where bile flow from the liver is blocked, this process can progress further. Bilirubin can be oxidized into biliverdin, a green pigment. This can result in a transition from a yellow to a greenish hue in the skin and eyes. This is a serious symptom requiring immediate medical attention, as it indicates a significant problem with the liver or biliary system.
Pseudomonas Infections
Certain bacterial infections can also cause green skin discoloration, particularly in burn wounds or compromised skin. The bacterium Pseudomonas aeruginosa is notorious for producing a blue-green pigment called pyocyanin and a yellow pigment called pyoverdine. The combination of these pigments can give infected wounds a distinct green coloration. A different manifestation, known as green nail syndrome (chloronychia), occurs when P. aeruginosa infects the area beneath a fingernail or toenail. The resulting green or blue-green color is trapped beneath the nail plate and does not wash off.
Chloromas
Chloromas are localized tumors of myeloid leukemia cells. These tumors are named for the greenish tint they can have when a fresh cut is exposed to air, though this color often fades. The green color is due to the presence of the enzyme myeloperoxidase within the cells. While rare, a chloroma can present as a skin lesion with a distinct greenish hue, though it may also be masked by the red color of blood vessels.
Exogenous and Environmental Factors
Not all cases of green discoloration are due to an internal medical problem. External factors can also cause temporary or localized changes in skin color.
Copper Exposure
One of the most common and non-threatening causes is contact with copper. Acidic sweat from the body can react with copper or copper alloys (like brass or certain plated metals found in jewelry) to form green copper salts. This is a common reason for a green ring around a finger. The discoloration is localized to the area of contact and can be washed off, though it may reappear with continued wear.
Dyes and Tattoos
Contact with green dyes from clothing or other textiles can temporarily stain the skin. A more permanent cause is the use of green tattoo ink, which deposits the pigment directly under the skin. Green hair can also occur in individuals with light-colored hair who swim frequently in pools with high copper concentrations.
Medications and Food Dyes
Some medications and food dyes can lead to systemic green discoloration, although this is extremely uncommon. A historical example includes the obsolete topical antimicrobial 'brilliant green.' In modern medical settings, blue food coloring (FD&C Blue No. 1) used in tube feedings for patients with multiple organ failure has been known to combine with the yellow of jaundice to cause a green discoloration.
Comparison of Internal vs. External Causes
To help differentiate between potential causes, this table summarizes key characteristics.
| Feature | Internal/Medical Causes | External/Environmental Causes |
|---|---|---|
| Symptom Scope | Often systemic (e.g., body-wide skin and eyes) | Usually localized (e.g., finger, wound, tattoo site) |
| Accompanying Symptoms | May include fatigue, pain, dark urine, pale stools, fever | None, or only localized inflammation/infection symptoms |
| Persistence | Chronic conditions cause persistent discoloration | Discoloration resolves with removal of cause |
| Onset | Gradual, associated with other illness symptoms | Sudden, following specific exposure |
| Urgency | Requires immediate medical evaluation | Often less urgent, self-diagnosable |
What to Do if You Notice Green Skin
If you or someone else develops green skin discoloration, especially if it is widespread or accompanied by other symptoms like yellow eyes, fatigue, or dark urine, it is imperative to seek immediate medical attention. A healthcare provider can run tests to check liver function, screen for infections, and identify the root cause. For localized discoloration, such as from jewelry, simply removing the item and washing the area is often enough. If the discoloration persists, a visit to a dermatologist is warranted.
Conclusion
While a person turning green is a dramatic and rare occurrence, it is a significant medical sign that should not be ignored. From the serious implications of obstructive jaundice and certain infections to the more benign effects of copper exposure, the causes are diverse. An accurate diagnosis relies on careful observation of the discoloration's extent, the presence of other symptoms, and a proper medical evaluation. Early intervention is key, especially when internal medical issues are suspected. For more information on the various conditions causing this symptom, it is best to consult authoritative medical sources, such as peer-reviewed dermatological studies. ScienceDirect - The color of skin: green diseases of the skin, nails, and mucosa
