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's melanosis’ or ‘pigmented hairy epidermal naevus’.

Becker’s 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. Although most commonly people will only have one Becker’s naevus, it is possible to have more.

What causes a Becker naevus?

What causes a Becker’s naevus is not fully understood. Although some children are born with a Becker’s 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.

It has been suggested that Becker naevi may express more receptors to male hormones (androgens), and exhibit increased sensitivity to them. This may explain why the majority of Becker naevi develop during or after puberty, are more common in boys and have a tendency to develop acne within the affected area.

Is a Becker’s naevus hereditary? 

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

What are the symptoms of a Becker naevus?

Becker naevus does not usually cause any problems, although some people may not like the appearance. Acne or, rarely, eczema can sometimes be present in a Becker naevus.

What does a Becker naevus look like?

It 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 at the affected skin. If 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?

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

How can a Becker naevus be treated?

Usually a Becker’s naevus is too large to be surgically removed. Different laser systems have been used to treat both the colour and the hair. Overall the excess hair responds better to laser treatment than the colour. Please note that these 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’s naevus, treatment of these skin conditions can be helpful. 

Self-care (What can I do?)

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

Where can I get more information about a Becker naevus?

Web links to detailed leaflets:

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

Jargon Buster: https://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

REVIEW DATE NOVEMBER 2023