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?
A keratoacanthoma (KA) is a relatively common, rapidly growing skin growth that usually develops on sun-exposed skin. A KA can look like a form of skin cancer called a squamous cell carcinoma (SCC). However, unlike an SCC, a keratoacanthoma is benign (not harmful).
What causes a keratoacanthoma?
The precise cause of KA is not known. However, environmental factors such as sun-exposure, smoking, older age, skin injury or a suppressed immune system may increase the risk of a KA occurring. More recently, certain drug treatments for melanoma have been shown to increase the risk of developing KA and you should discuss this with your doctor if you have previously been diagnoses with melanoma and are worried.
Are keratoacanthomas hereditary?
Usually not but there are very rare genetic conditions that can lead to multiple skin cancers in individuals and their family members.
What does a keratoacanthoma look and feel like?
Sometimes, a KA can feel itchy or painful. KAs occur most commonly on sun-exposed areas of the skin like face, backs of the hands and forearms. They are usually single lesions and surrounded by normal skin. They may appear similar to a small pimple or boil initially, then grow rapidly over a few weeks, 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 that you see an expert such as a dermatologist. If the diagnosis is not clear, then they often remove the growth to be examined under a microscope to confirm it is not a SCC.
How can a keratoacanthoma be treated?
If left alone a KA can shrink and disappear, leaving a scar.
KAs can be scraped away (curettage) under a local anaesthetic and the base is burnt (cauterised). There is a chance that the KA may recur if the base is not removed completely. More often 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.
Occasionally, small KAs can be treated by freezing with liquid nitrogen (cryotherapy). Alternatively, KA may be treated with a topical or intralesional (via injection) chemotherapy.
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 (SPF) 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:
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 | AUGUST 2005
UPDATED | MAY 2010, MAY 2013, NOVEMBER 2016, NOVEMBER 2019, AUGUST 2023
NEXT REVIEW DATE | AUGUST 2026