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Patient Information Leaflets (PILs)


What are the aims of this leaflet?

This leaflet has been written to help you understand more about keratoacanthoma (KA). 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 keratoacanthoma?

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

What causes a keratoacanthoma?

Their precise cause is not known.

KA tends to occur on sun-exposed skin. It is more frequently seen in white skinned individuals and in those over 60 years of age.

Are keratoacanthomas hereditary?

Usually not. 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 more frequently on the face, and less often on the backs of the hands and forearms. Usually they are solitary and surrounded by normal skin.

The lesion may appear as a small pimple or boil initially. It grows rapidly over a few weeks to months. The small pimple or boil then becomes a firm lump with a horn or scale in the centre. Sometimes, the centre can erupt and form a crater.

How will a keratoacanthoma be diagnosed?

As the lesion can look similar to a skin cancer, it is important for the lesion to be removed at an early stage to have the diagnosis confirmed under the microscope. Your doctor is likely to refer you to a dermatologist who then performs the skin surgery to remove the lesion.

Can a keratoacanthoma be cured?

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

How can a keratoacanthoma be treated?

If left alone, KA can eventually resolve leaving a scar. However, it is recommended to have the lesion removed to confirm that it is not a skin cancer.

One method of removal is to scrape the KA off with a sharp, spoon-like instrument (a curette) 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.

The entire lesion of KA can be cut out (excised) and the area closed with stitches.  Once the entire lesion is removed, it is unlikely to recur.

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:

For details of source materials used please contact the Clinical Standards Unit (

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


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