What are the aims of this leaflet?

This leaflet has been written to help you understand more about a Becker naevus. It tells you what it is, what causes it, what can be done about it, and where you can find out more about it.

What is a Becker naevus?

‘Naevus’ is the Latin word for birthmark. It is called Becker after the name of the American dermatologist that described it. Becker naevus is sometimes called ‘Becker melanosis’ or ‘pigmented hairy epidermal naevus’.

Becker naevus usually develops in the second or third decade of life. It can occur in all skin types and is more common in boys than girls. It is thought to occur in 0.5% of the adult male population. Although most commonly people will only have one Becker naevus, it is possible to have more.

What causes a Becker naevus?

The cause of Becker naevus is not fully understood. Although some children are born with a Becker naevus, it usually appears during childhood and early teenage years. One theory is that from birth some people have a small patch of skin with the predisposition to a Becker naevus.

Research suggests that Becker naevi are more sensitive to male hormones (androgens). During puberty, androgen levels rise in the body as part of natural development, especially in boys. This may explain why most Becker naevi develop during or after puberty, and why it is more common in boys more than in girls.

Is a Becker naevus hereditary? 

No. Although there are some reports of Becker naevus occurring in more than one family member, it does not run in families. 

What  Becker naevus feel and look like?

Becker naevus does not usually cause any problems. Some people may dislike its appearance. Acne may develop occasionally within the naevus, and in rare cases, eczema can also occur.

Becker naevus is a well-defined patch of darker skin with excessive hair. The skin may appear slightly thickened. It is usually located on the shoulders or trunk. Rarely, it can be found on the legs. Usually only the skin is affected however, rarely the underlying tissues can be affected, for example the breast, the muscles, the underlying fat tissue and the bones. This is known as Becker naevus syndrome.

Because this patch of skin is thought to be more sensitive to male hormones, it can become more prominent and with more hairs during puberty.

How is a Becker naevus diagnosed? 

The diagnosis is often made by clinically examining the affected skin.  If your healthcare professional is unsure, then a dermatologist may be asked to review.

Sometimes, a small skin sample (known as a skin biopsy) may be taken and checked under the microscope to confirm the diagnosis. 

Can a Becker naevus be cured?

Currently, there is no cure for Becker naevus. It will not go away on its own.

How can a Becker naevus be treated?

Becker naevi are too large to be removed surgically. Currently, there are different laser options available to treat both the colour and the hair of the naevus. However, these treatments have been shown to be more effective against the excess hair of the naevus but not the colour.

Please note that laser treatments may not be available on the NHS; your primary care physician may be able to suggest a suitable clinic for laser treatment.

If there is acne or eczema within the Becker naevus, treatment of these skin conditions can be helpful. Your healthcare professional will advise you on this.

Some people may prefer to use camouflage makeup to conceal the naevus, especially if they have concerns about its appearance following hair removal. 

Self-care (What can I do?)

The hair on a Becker naevus can be safely removed by shaving, waxing, threading or using epilation creams; these will not increase the hair-growth.

Where can I get more information about a Becker naevus?

Web links to other relevant sources:

www.dermnetnz.org/lesions/beckers-naevus.html

Jargon Buster: www.skinhealthinfo.org.uk/support-resources/jargon-buster/

Please note that the BAD provides web links to additional resources to help people access a range of information about their treatment or skin condition. The views expressed in these external resources may not be shared by the BAD or its members. The BAD has no control of and does not endorse the content of external links. 

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: individual patient circumstances may differ, which might alter both the advice and course of therapy given to you by your doctor. 

This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel

BRITISH ASSOCIATION OF DERMATOLOGISTS PATIENT INFORMATION LEAFLET

PRODUCED | OCTOBER 2013

UPDATE | JANUARY 2018, NOVEMBER 2020, FEBRUARY 2025

NEXT REVIEW DATE | FEBRUARY 2028

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