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Have irregular black spot on arm. What could it be?

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Pediatrician, Infectious Diseases
Practicing since : 2005
Answered : 1528 Questions
I have an irregular shape black spot on my arm that recently has turned white??
Sat, 12 Jan 2013 in Skin Hair and Nails
Answered by Dr. Hema Yadav 10 hours later
Thanks for posting your query.
An irregular mole which changes colour can be indicative of a skin cancer like melanoma.
The difference between an ordinary mole and a life-threatening melanoma can be as follows.

1.Asymmetry - most moles are symmetrical. If you drew a line through the middle, the two halves would mirror each other. Melanomas are asymmetric: their two halves are not mirror images.
2.Border - most moles have a distinct border. The border of a melanoma is likely to be notched, scalloped or indistinct.
3.Color - moles may be either dark or light, but they tend to be the same color. Early melanomas are more likely uneven in color or a mixture of different hues.
4.Diameter - a melanoma, is also likely to be more than six millimeters wide (the size of a pencil eraser).
Considering the colour change which usually occurs in dead cancerous tissue I would advise you not to neglect it.
So I would recommend you get it examined by your doctor and investigated ( biopsy if indicated) to confirm the diagnosis and start further management .
Hope I have answered your query.
Wishing you good health.
Above answer was peer-reviewed by
Follow-up: Have irregular black spot on arm. What could it be? 14 hours later
I have looked on line to compare pictures. It looks almost identical to a picture identified as Actinic Kertosis The spot is irregular and flat about the size of a dime. The white spots within the area are slightly raised and will scape off or wash off and then return after a while
Answered by Dr. Hema Yadav 8 hours later
Hello ,
Thanks for the follow up.
Yes irregular scaly rough patches could be actinic keratosis . However it is usually known to occur in frequently sun damaged skin like face , hands , ears etc.
Another feature is that it's frequently multiple in number and develops over many years.The fact that you can rub off thick scales from your lesion does make it more likely a keratosis.
Actinic keratoses are precancerous, which means they can develop into squamous cell carcinoma ( skin cancer.)
Doctors can usually diagnose an actinic keratosis just by examining it or in some cases by biopsy.
The best treatment for an actinic keratoses is prevention by minimizing sun exposure.
Treatments for actinic keratoses include cryosurgery, cutting or burning, 5-fluorouracil, imiquimod, diclofenac, and photodynamic therapy.
So I would recommend you get it examined by your dermatologist as soon as feasible for confirmation and management .
Hope I have answered your query .
Wishing you good health.

Above answer was peer-reviewed by
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