You are doing a great job of maintaining hygiene. You are also correct to presume this is pseudomonas, the most common bacterial cause of green nails. However, in odd and persistent cases like this, one must also consider other bacterial and fungal causes. The client should see a doctor to get cultures of the nail for evaluation. People with constant infections may also have other hidden medical conditions, like diabetes. Finally, many people are also colonized by the culprit causing the infection. Topical medications can bring the infection under control. — Dr. Rashid M. Rashid is a house staff dermatologist at the University of Texas MD Anderson Cancer Center and director of the nail, hair, and skin disease division of the Morzak Center.
[Editor’s Note: Dr. Rashid’s comments are for educational purposes only. They are not a medical opinion, nor should they substitute for medical evaluation and treatment.]