Becker's naevus

What is Becker’s naevus?

Becker’s naevus is a benign (non-cancerous) epidermal naevus or birthmark characterised by a large brown patch usually arising in children or young adults and typically affecting the shoulders or upper trunk. It is more common in males than females.

What does Becker’s naevus look and feel like?

• In the majority of cases there is only one area of affected skin

• Usually there are no symptoms
  
  
• The shoulder, chest, and upper back are the most commonly affected sites; other parts of the skin are occasionally affected. Normally only one side of the body is involved
  
  
• There are normally three developmental stages:
  • The development of irregular flat brown patches
  • The patches come together to form a large patch of pigmentation, which tends to be quite even in colour. The pigmentation is often quite light but becomes darker when exposed to the sun
  • Over time an overgrowth of thick, dark hair occurs, and the skin texture becomes thickened towards the centre. Occasionally acne spots can develop

What causes Becker’s naevus?

Becker’s naevus is caused by an overgrowth of the upper layer of skin (the epidermis) and hair follicles. It has been suggested that the affected skin is more sensitive to androgens (the predominant male hormones). They are not hereditary (i.e. do not run in families).

Make an appointment at your GP surgery

Although Becker’s naevus is permanent, it is harmless and requires no treatment. The main issues are cosmetic:

• Protecting the affected area from the sun will keep the lesion paler and make it stand out less
• The hair can be safely removed by, e.g. shaving, waxing, or using epilation creams - these will not increase the hair-growth. Hair can also be removed by laser or electrolysis, but even then the hair may regrow

Referral to a specialist

Referral to a specialist is not normally needed. Treatment of these lesions is very difficult and for most there is no satisfactory outcome:

• Cosmetic camouflage may be used but is often unsatisfactory as a result of the excess hair, although physical methods of hair removal may be of benefit and are not harmful

• Laser therapy has been used but results are often disappointing and such treatment is usually only available on a private basis

Your mental health

If the appearance of the Becker’s naevus is affecting your mental health and/or relationships, you should discuss this with a health professional.

Helping with other skin conditions

If you, a family member, or friend have an undiagnosed skin condition; or you want to learn more about how to treat skin conditions, please view our short video on how to get the best from this website.