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Keratoacanthoma

KERATOACANTHOMA

What are the aims of this leaflet?

This leaflet has been written to help you understand more about keratoacanthomas (KA). It tells you what they are, what causes them, what can be done about them, and where you can find out more about them.

What is a keratoacanthoma?

KA is a relatively common, rapidly growing skin growth that usually develops on sun-exposed skin. It starts in skin cells that surround the hair follicle. Early diagnosis is needed to differentiate a keratoacanthoma from a skin cancer called squamous cell carcinoma (SCC). However, unlike an SCC, a keratoacanthoma is benign.  

What causes a keratoacanthoma?

The precise cause of KA is not known. However, sun-exposure, smoking, older age, skin injury, a suppressed immune system, and more recently certain drug treatments for melanoma (BRAF inhibitors) have been shown to increase the likelihood of developing KA. 

Are keratoacanthomas hereditary?

Usually not; however, rarely KA can be due to genetic conditions in those who have multiple lesions and a history of other affected family members. 

What are the symptoms of a keratoacanthoma?

Sometimes KA can feel itchy or painful.

What does a keratoacanthoma look like?

KAs occur most commonly on sun-exposed areas of the skin, more frequently on the face, and less often on the backs of the hands and forearms. They are usually solitary and surrounded by normal skin. They may appear similar to a small pimple or boil initially, then grow rapidly over a few weeks to months, becoming a firm lump with a crater in the centre looking like a volcano.

How will a keratoacanthoma be diagnosed?

As KAs can look similar to a skin cancer, it is important for it to be removed at an early stage. Your doctor will refer you to a dermatologist who would remove the growth which will be examined under a microscope to give an accurate diagnosis.

Can a keratoacanthoma be cured?

Yes, once the KA is removed, it is considered cured.

How can a keratoacanthoma be treated?

If left alone, KA can eventually shrink and disappear leaving a scar. However, it is recommended that the growth is removed to confirm it is not a skin cancer.

The entire KA can be cut out (excised) and the area closed with stitches. It is unlikely to recur if it has been completely removed. 

Another method of removal is to scrape the KA away (curettage) under a local anaesthetic and cauterize the raw area left behind. The specimen that has been scraped off is sent for microscopic examination. There is a chance that the KA may recur if the base is not removed completely.

Occasionally, small KAs can be treated by freezing with liquid nitrogen (cryotherapy).

Self-care (What can I do?)

If you have had a KA, it is advisable that you check your skin regularly for any new lumps or bumps and avoid getting sunburnt. You should use a high factor (minimum sun protection factor 30), broad spectrum sunscreen (which blocks both types of ultraviolet radiation, UVA and UVB) on the exposed areas such as your face and hands.

Where can I get more information about keratoacanthomas?

Web links to detailed leaflets:

www.dermnetnz.org/lesions/keratoacanthoma.html

For details of source materials used please contact the Clinical Standards Unit (clinicalstandards@bad.org.uk).

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 AUGUST 2005
UPDATED MAY 2010, MAY 2013, NOVEMBER 2016, NOVEMBER 2019
REVIEW DATE NOVEMBER 2022

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Keratoacanthoma

KA is a relatively common, rapidly growing skin growth that usually develops on sun-exposed skin. It starts in skin cells that surround the hair follicle. Early diagnosis is needed to differentiate a keratoacanthoma from a skin cancer called squamous cell carcinoma (SCC). However, unlike an SCC, a keratoacanthoma is benign.  

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