Nail Fungus or Melanoma, How Can You Tell the Difference?

I saw my big toe nail today during a pedicure and noticed that part of it is blackish greenish in color. I have a history of melanoma insitu and wonder if I am over reacting to simple nail fungus or could this be Acral lentiginous melanoma?

Doctor Answers 3

Check It Out

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I am in full agreement with my dermatology colleagues. Most sub-ungual melanomas arise on the first toenail (the great toe).  If you are Caucasian this is particularly worrisome, especially in someone with a history of a melanoma-in-situ. 

While there are some signs that help us differentiate a benign condition such as a fungus from melanoma ( a straight  border,  even pigment throughout , lack of Hutchinson sign, which is the creeping of pigment onto the skin surrounding the nail), this is for the expert dermatologist and not a lay person to determine.

  The green color also is somewhat comforting as this is much more likely to be found in a fungal state or as Dr. George, mentions Pseudomonas infection. ( Pseudomonas is a strange organism. in the ear canal ( external otitis) it is easily cured. Same for pseudomonas nail infection. However,  in the lung it is deadly, and in my pathology days, it seemed to be nearly ubiquitous as a cause of death. Most end stage disease, cancer or heart, results in a pneumonia. Also, one of its by-products, Bactroban, has proven to be invaluable in the treatment of topical skin infections.

  So, now you have three dermatologists advising you to see your dermatologist. 

Virginia Beach Dermatologist

Fungus vs. Melanoma

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I agree with Dr. George completely. Sounds fungal and /or bacterial but need to get it checked anyway. Does not sound like you need panic. 

Jo Herzog, MD
Birmingham Dermatologist
4.8 out of 5 stars 20 reviews

Melanoma vs. Fungus in the nail

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With your history of melanoma in situ I would recommend you see a dermatologist to ensure that this is not a melanoma, however there are some clinical cues that may be helpful. Typically melanomas will show pigment not only within the nail, but also around the nail bed. This is called Hutchinson's sign. The greenish color you describe sounds like it could be a bacterial infection caused by Pseduomonas, but since melanoma doesn't always follow the textbooks it is still a good idea to have it checked.

Rosalyn George, MD
Wilmington Dermatologic Surgeon
4.4 out of 5 stars 12 reviews

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