Becker's nevus

Alternate names

Becker melanosis; Becker nevus; Becker naevus

Definition

• Becker's nevus is a non-cancerous, large, brown birthmark occurring mostly in males.
• In very rare cases, Becker's nevus is associated with other skin features; muscular or skeletal features; or underdevelopment (hypoplasia) of the breast. When this occurs, the condition is known as Becker's nevus syndrome.

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Cause

• Becker's nevus is due to overgrowth of the epidermis (upper layer of the skin), pigment cells (melanocytes) and hair follicles.
• The specific underlying cause is unknown.
• Because it often forms around puberty in males and is sometimes associated with acne and hair growth, its development may be triggered by androgens (male sex hormones such as testosterone).

Onset

It can be present at birth, but is usually first noticed around puberty.

Signs and symptoms

• A Becker's nevus typically begins to develop around puberty on the shoulder or upper trunk, although it may develop on other areas of the body.
• It is sometimes present from birth.
• Pigmentation (darkening of skin color) may be subtle at first, but the nevus often darkens after puberty and expands.
• The resulting birthmark is usually large, brown, and on one side of the body.
• The nevus may grow more hair than the surrounding skin.
• In some cases, acne develops within the nevus.

Diagnosis

The diagnosis of Becker's nevus is based on clinical features, a biopsy may be necessary to rule out other related conditions.

Treatment

• Becker's nevus typically does not require treatment except for cosmetic reasons - primarily excessive hair growth (hypertrichosis) and hyperpigmentation.
• Treatment has always been challenging, often using lasers with mixed results.
• Q-switched ruby laser has been used with variable success in the treatment of both the hypertrichosis and hyperpigmentation.
• Hypertrichosis may also be improved by laser-assisted hair removal or by electrolysis.
• Hyperpigmentation may be lessened with Q-switched Nd:YAG laser or fractional resurfacing, although responses are variable and recurrence rates are high.
• Acne that develops within the nevus can be treated with standard acne therapies.
• People with Becker's nevi should be examined for associated soft tissue and bony abnormalities.

NIH genetic and rare disease info

• NIH info on Becker's nevus

Becker's nevus is a rare disease.

Becker's nevus Resources
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