Disseminated superficial actinic porokeratosis

What is disseminated superficial actinic porokeratosis? 

DSAP is a skin condition manifested by multiple, dry, scaly rings, each measuring up to 1 cm (1/2 inch) across. They are found mainly on the forearms and legs. It is due to excessive sun exposure causing thickening of the skin. It is sometimes confused with actinic keratosis which is also caused by sun exposure (See Patient Information Leaflet on Actinic Keratoses); however, actinic keratosis is more likely to arise on the face and hands.

DSAP is twice as likely to develop in women compared with men and is more common in lighter skin type. Itnormally develops between 30-50 years of age. It is not contagious.

What causes disseminated superficial actinic porokeratosis?

Sun and/or ultraviolet light exposure causes DSAP. This condition tends to affect people with fair skin who burn easily and tan poorly in the sun. It may appear more obvious in summer and less obvious in winter. The best way to stop this skin condition from worsening is to avoid sun exposure (including sun beds). Patients taking medication or with illnesses that weaken the body’s immune system are also more likely to develop this skin condition.

Is disseminated superficial actinic porokeratosis hereditary?

Yes. On average about half of the children of an affected parent could develop DSAP, although a certain amount of accumulated sun exposure is required for it to appear.

What are the symptoms of disseminated superficial actinic porokeratosis?

DSAP is usually asymptomatic. The affected areas often feel dry and rough. However exposure to sun can cause them to itch and grow in size (still remaining small) and number.

What does disseminated superficial actinic porokeratosis look like?

DSAP normally starts as a brownish red or brown spot and can grow from 2 mm up to 2 cm (1/2 inch) in diameter. The affected area normally has a thinned centre surrounded by a ridge-like border.

DSAP itself is harmless. However many people with DSAP have had significant exposure to the sun and so may also have other skin lesions caused by sun damage including skin cancer. It is therefore important to see your GP or skin specialist if you notice any new or changing skin lesions.

How is disseminated superficial actinic porokeratosis diagnosed?

A sample of the affected area may be removed under local anaesthetic by a dermatologist for microscopic examination in the laboratory (known as a skin biopsy). However, the appearance of the affected area, along with the history, may enable a doctor to make the diagnosis.

Can disseminated superficial actinic porokeratosis be cured?

Unfortunately there is no cure for DSAP. The best way to avoid worsening of this skin condition is to avoid exposure to the sun and regular use of sunblock.

To find out about available treatments please visit this page on the website of the British Association of Dermatologists.

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