What is Becker Melanosis (Becker Nevus)?
Becker’s melanosis, also known as Becker’s nevus, is a type of skin darkening or discoloration that someone can develop later in life. In 1949, William Becker first encountered this condition in two case studies, describing it as “having both skin darkening and excessive hair growth in the area of a birthmark on one side of the body.”
What Causes Becker Melanosis (Becker Nevus)?
The exact cause is not fully understood. Becker’s melanosis is thought to be a harmless, late-developing type of skin growth called an epidermal nevus. Certain features, such as development during puberty, being more common in males, excess hair growth and acne-like spots suggest that male hormones, known as androgens, may play a role. Some reports indicate an increase in the number of androgen receptors associated with the condition.
Risk Factors and Frequency for Becker Melanosis (Becker Nevus)
Becker melanosis is a condition that mainly affects males, with the ratio of males to females being about 5:1. Its estimated prevalence among males is 0.5%. Usually, this condition appears during puberty. However, there have been rare instances where Becker melanosis shows up at birth or in early childhood. There have also been reports of this condition occurring within families. Research suggests that it occurs more commonly among people with darker skin.
- The condition predominantly affects males with a ratio of approximately 5 males for every female.
- About 0.5% of males experience Becker melanosis.
- This condition most commonly makes its first appearance during puberty.
- Rare cases have been reported where Becker melanosis presents at birth or early childhood.
- This condition can also occur within families.
- Studies suggest that Becker melanosis is more common in people with darker skin.
Signs and Symptoms of Becker Melanosis (Becker Nevus)
Becker melanosis is a skin condition that appears as a clearly demarcated, one-sided, dark tan or brown patch. This patch usually expands in size and may take on an irregular, map-like pattern. In many cases, it shows up primarily on the right side of the body. The most common places we see it are the shoulder, the area around the shoulder blade, and the upper arms. Though it’s not common, Becker melanosis sometimes appears as patches on both sides of the body and on unusual spots like the lower legs.
Sometime after the dark patch becomes noticeable, hair often starts to grow in the affected area. This can take anywhere from months to years to happen. Sometimes, pimples may also appear on the patch. In some instances, Becker melanosis could be linked to Becker nevus syndrome, which involves additional physical abnormalities. These can include benign skin growths made up of smooth muscle cells (smooth muscle hamartomas), underdevelopment of the breast, shoulder muscles and fat, enlarged limbs, an overgrown adrenal gland, and an additional scrotum. A very rare link with melanoma, a type of skin cancer, has also been reported.
Once the Becker melanosis patch has appeared, it usually remains for the rest of a person’s life. If hair does start to grow on the patch, it generally happens after the skin has darkened and tends to become increasingly thick with time. Recent studies have suggested that hair growth might not occur in most people with Becker melanosis.
Testing for Becker Melanosis (Becker Nevus)
Diagnosing this skin condition often relies heavily on visual checks and physical examinations. However, a skin biopsy may be used for confirmation. This involves taking a small sample of skin and examining it under a microscope. Findings may include mild thickening of skin cells and excess skin pigment, or melanin, in the lower layer of the skin. Although the number of melanin-producing cells is usually normal, the skin may appear darker. Another observation might be the presence of melanophages, which are cells that eat melanin, in the layer beneath the skin.
Other microscopic abnormalities may include elongation of the skin’s structures, an increased number of muscle cells in the skin, and the overgrowth of sebaceous or oil glands. Recent studies have also reported too many skin cells, pigment cells, muscle fibers that cause hair to stand on end, and nerve fibers in the skin.
Additional tests have shown that there might be an increase in specific proteins or markers, like Ki-67, melan-A , and keratin 15in the skin with the condition compared to normal skin. The length of nerve fibers and the level of a protein that helps muscle contraction, known as smooth muscle actin, have also been found to be higher in the affected skin.
Treatment Options for Becker Melanosis (Becker Nevus)
Becker melanosis is a skin condition that involves skin darkening, or hyperpigmentation. While the skin darkening can often remain the same, in some cases, it has been noted to fade by itself. Treatment for Becker melanosis is mostly for improving the look of the skin, especially during the rapid changes that occur in adolescence.
Lasers are a common method of treatment for both the darkening and the excessive hair growth (hypertrichosis) which sometimes comes with it. There are several types of lasers that work well for Becker melanosis, such as the Q-switched Ruby laser, Q-switched Nd YAG, long-pulsed Alexandrite, and multiple types of fractional ablative lasers. The most frequent ones used are the Q-switched ruby and the Q-switched Nd YAG lasers. However, these lasers do have a high chance of the condition coming back.
If excessive hair growth is present, combinations of fractional lasers with hair removal lasers have been shown to help. The 1550 nm non-ablative laser, for example, is often effective when combined with hair removal lasers. Optimal results usually require multiple treatment sessions, and electrolysis may also work well for treating hypertrichosis.
People with Becker melanosis are advised to protect their skin from the sun, as sun exposure might make the skin look darker. Some patients may also develop a condition that causes acne-like lesions, and these can often be improved by using skin cream with retinoids.
Another complication that can be associated with Becker melanosis is breast hypoplasia, which involves unequal breast development. One effective treatment for this issue is called breast lipofilling, where the cosmetically smaller breast is augmented by grafting fat into it.
Lastly, makeup can be used to help conceal hyperpigmentation, which can significantly help with improving self-esteem and overall quality of life, especially when the lesions are in noticeable areas.
What else can Becker Melanosis (Becker Nevus) be?
When a doctor is trying to diagnose Becker’s melanosis, which is a skin condition that can cause dark, patchy areas to appear, they consider several other conditions that might cause similar symptoms. These include:
- Albright syndrome, a genetic disorder that can affect the skin and bones
- Congenital melanocytic nevus, a type of birthmark that appears at birth or in the first year of life
- Congenital smooth muscle hamartoma, a birthmark often present from birth or noticed in the first year of life
- Overdevelopment of certain pieces of tissue such as adrenal gland, limb, fingers, or toes
- Post-inflammatory hyperpigmentation, where skin becomes darker after it has been damaged
- Smooth muscle hamartoma, a rare, benign, skin growth often present at birth or in early infancy
- Underdevelopment of underlying structures such as the breast, body fat, limb, etc.
Each of these conditions has its own symptoms and characteristics, so it’s important for the doctor to consider them all before making a diagnosis.
