Penile melanosis is usually a benign or harmless condition. It’s characterized by small patches of dark skin on the penis. This change in color is known as hyperpigmentation, and it occurs when melanin (brown pigment) forms deposits in the surface layer of skin.

Penile melanosis is also known as penile lentiginosis. The spots or lesions of darker skin can form on the head or shaft of the penis. The condition is normally harmless and doesn’t require treatment. It’s also not infectious.

Other than the dark spots (also known as macules), there are no health symptoms associated with penile melanosis. The main signs are macules that are:

  • usually brown or black
  • under a centimeter in length
  • present between the ages of 15 and 72, though they can appear at any age
  • painless and not likely to bleed or change over time

Someone with this condition may have a single dark spot or many spots. There is no way to predict how many macules, if any, a man will have.

In rare cases, penile melanosis is related to a condition called lichen sclerosus. It involves thinning of skin on the penis and the presence of whitish spots on the penis head or foreskin.

Topical medications are sometimes enough to treat lichen sclerosus, which is believed to be caused by a hormone imbalance or an abnormal response of the immune system. Topical steroids and other medications don’t affect the pigment changes brought on by penile melanosis, however. Lichen sclerosus is often located on the foreskin of uncircumcised males. Removal of the foreskin is sometimes necessary to treat it.

It’s not clear why some men develop penile melanosis and others don’t. The macules are simply the collections of concentrated amounts of melanin or other pigmentary deposits, such as hemosiderin and lipofuscin, in the skin. One study reports that a man’s race and genetic makeup may play a role in the risk of developing the condition.

Other possible causes may include injury to the penis, treatment with the psoriasis medication anthralin, or psoralen and ultraviolet light (PUVA) therapy, which is used to treat psoriasis, eczema, and other skin conditions.

Penile melanosis isn’t a sexually transmitted infection — in fact, it doesn’t represent an infection of any kind.

Typically, no treatment is required or recommended for penile melanosis. For some men and adolescent boys, simply getting reassurance from their doctor about the harmless nature of the condition is helpful. For example, it’s important to know that the condition is benign and not contagious.

Removal options

If you’re bothered by the appearance of macules on your penis, you may be a candidate for surgical removal of the lesions. The procedure includes the removal of the skin layer containing the excess pigment, as well as a skin graft and resurfacing the skin to an acceptable appearance and thickness.

Laser therapy to remove them may also be possible. The type of laser involved is a Q-switched ruby laser, which uses a synthetic ruby and emits concentrated, short laser pulses. It’s a common treatment for pigment-related dermatological conditions. Several sessions may be necessary to fully remove lesions.

These procedures can leave small scars, though they are usually safe and don’t affect the health and function of the penis. Be sure to discuss all the risks and benefits of these procedures before committing to a treatment plan.

There is no way to prevent penile melanosis. It’s an unpredictable condition. Your doctor should, however, keep an ongoing photographic record of the macules to check for any changes in shape or size over time. Although unlikely, such changes might signal melanoma, a dangerous form of skin cancer.

No physical complications are associated with penile melanosis. The condition can trigger anxiety and stress, however. If these reactions become too serious, you should have a lengthy conversation with your doctor about your concerns and treatment options.

Because penile melanosis is a noncancerous condition, its outlook is very good. While there is no direct evidence that penile melanosis is a precursor to melanoma, it can still cause anxiety. The more you learn about penile melanosis and talk with your dermatologist about it, the more relaxed you should feel about this harmless condition.