Medically reviewed by The Dermatologists and written by Dr. Alexander Börve
- Requires medical diagnosis
- Symptoms: Itchy firm bumps
- Color: Typically red-purple, tan/brownish
- Location: Commonly on the lower legs, upper arms and upper back
- Treatment: No treatment necessary; freezing, shaving off the top
A dermatofibroma also called histocytoma, is a firm, small, lightly pigmented benign growth of the dermis (deeper layer of the skin) which is harmless. The growth may be elevated after insect bites or a splinter. The condition usually appears on legs or upper arms and most often affects adult women.
They are a common overgrowth of the fibrous tissue situated in the dermis (the deeper of the two main layers of the skin). Therefore, it is also more common in immune deficient individuals.
A dermatologist can easily identify by the way it looks in most cases.
Dermatofibromas are firm bumps that can be itchy and tender. These lumps often start as red-purple, and then turn to tan/brownish. They rarely grow larger than a half-inch in diameter. The cause is unknown.
They are usually round and occur most commonly on the lower legs, upper arms and upper back. The lumps are hard, while the skin surface is smooth or scaly. They often feel like a stone under the skin, as the lumps form deep into the skin. When pinched from the sides, the top of the growth may dimple inward.
The bumps are usually painless, but may itch or hurt when you touch them. In most case only a single nodule develops, but some people may experience several.
What can I do?
Because no one knows what causes it, there is no way to prevent them. Keep them under observation. If you want to remove them, you will have a scar.
Should I seek medical care?
They usually lasts indefinitely but are harmless. You do not need treatment, but it is always good to get an accurate diagnosis for reassurance. See a doctor immediately if the growth bleeds, grows quickly or becomes painful.
Removal is not necessary since they are harmless and not cancerous. Surgical removal usually leaves a scar. Other methods of removal involve freezing with liquid nitrogen and shaving off the top. They can be similar in appearance to a melanoma, so it is important to consult a physician if there is any doubt the lesion is not a fibroma.
American Osteopathic College of Dermatology. Available at: https://www.aocd.org/page/Dermatofibroma
Harvard Health Publications. Available at: https://www.drugs.com/health-guide/dermatofibroma.html
British Association of Dermatologist. DERMATOFIBROMA (ALSO KNOWN AS HISTIOCYTOMA). Available at: http://www.bad.org.uk/shared/get-file.ashx?id=78&itemtype=document
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