Becker's Nevus: Causes, Symptoms, and Treatment
Medically reviewed by Achuta Uppu, MD, Internal Medicine. Last reviewed: October 23, 2026.
What kind of doctor treats Becker's Nevus?
A dermatologist, a doctor who treats skin conditions, diagnoses and manages Becker's nevus. A primary care doctor can also look at the patch first and refer you. A direct primary care or concierge doctor can be a first stop for an evaluation and can refer you to a specialist when needed.
What is Becker's nevus?
Becker's nevus is also called Becker melanosis. It is a harmless skin problem that shows up after birth. It makes a patch of skin darker. The tan or brown patch grows on one side of the body. It most often starts in the teen years. Later it may grow extra hair.
A doctor named S William Becker first described it in 1949. Men get it about five times more often than women. About 0.5 percent of men are thought to have it.
Symptoms
Signs include:
- A tan or brown patch with a clear edge, on one side of the body. It grows slowly over time, often into a shape like a map.
- It most often shows up on the shoulder, the shoulder blade area, or the upper chest, back, and arms.
- Extra hair growing on the patch. The hair usually shows up after the skin darkens. It can take months to years to appear. Over time the hairs get coarser.
- Acne-like bumps may also grow on the patch.
The patch does not hurt or itch.
Causes and who gets it
The exact cause is not clear. The patch starts around puberty, it is much more common in males, and it comes with extra hair and acne-like bumps. All of this suggests that androgens, which are male hormones, play a role. An increase in the number of androgen receptors has been reported in the patch. Studies have also found gene changes that happen after fertilization, in the beta-actin gene, in some cases. Some studies show a higher incidence among Black individuals.
How doctors diagnose it
Doctors mostly diagnose it by looking at the skin. A skin biopsy may be done. This test removes a small piece of skin to study. It shows thickened skin layers and more melanin, the dark skin pigment, in the lowest skin layer. The number of melanocytes, the cells that make pigment, is usually normal.
Treatment
Becker's nevus is harmless. Most people worry about how it looks. The dark patch usually stays the same. Some cases fade on their own. Treatment is mainly for looks, not for health.
- Laser treatment can help both the darkening and the extra hair. The most used types are the Q-switched ruby laser and the Q-switched Nd:YAG laser. It takes more than one session to get the best result. The patch can also come back after laser treatment.
- Hair-removal lasers and electrolysis, a method that removes hair one by one using a tiny electric current, have been reported to work well on the extra hair.
- Acne-like bumps get better with topical retinoids, which are vitamin A skin creams.
- Protect the patch from the sun. Sun exposure might make it look darker.
- Cover-up makeup can help, especially on areas that show.
When to see a doctor
See a doctor if a dark patch with extra hair shows up, especially around puberty. A dermatologist can tell you what it is. Get a skin patch checked right away if it grows fast, changes color, or has an odd shape. In rare cases this condition has been linked with melanoma, a type of skin cancer. Some people also need follow-up for related nerve or spine problems.
How a direct primary care or concierge doctor fits in
A direct primary care doctor charges a flat monthly fee instead of billing insurance, while a concierge doctor usually charges more and often works alongside insurance. This doctor can look at the skin patch first and rule out other causes. The doctor can also refer you to a specialist for associated problems and help with long-term follow-up.
Common questions
Is Becker's nevus skin cancer?
No, it is a benign acquired hyperpigmentation disorder. A rare association with melanoma has been reported, so doctors watch the lesion and check any changes.
What causes Becker's nevus?
The exact cause is not clear. It starts around puberty. It is much more common in males. It comes with extra hair and acne-like bumps. All of this suggests that androgens, which are male hormones, play a role. The patch also has more androgen receptors than normal skin.
Does the hair and dark patch need treatment?
Treatment is mainly for looks, not for health. Laser treatment can help both the darkening and the extra hair. It takes more than one session to get the best result. The patch can also come back after laser treatment.
Can Becker's nevus be prevented?
There is no known way to prevent it. Sun protection is advised, as sun exposure might make the lesions appear darker.
Sources
- StatPearls (NCBI Bookshelf) - Becker Melanosis
- American Family Physician - Large, Dark Lesion on the Arm Present Since Birth
Medical Disclaimer
This content is for general educational and informational purposes only and is not medical advice. It is not a substitute for professional medical advice, diagnosis, or treatment, and reading it does not create a doctor-patient relationship. Always seek the advice of your physician or another qualified health provider with any questions about a medical condition, and never disregard or delay seeking professional advice because of something you read here. If you think you may have a medical emergency, call 911 (or your local emergency number) immediately.
