Actinic keratosis on the foot: what to know

An actinic keratosis is an area of sun-damaged skin that may feel rough, scaly or crusted. On the foot, the upper surface and exposed ankle are more typical sun-exposed sites than the sole or spaces between the toes. A spot in a covered area needs a careful look because a wart, fungal problem, eczema, friction injury or another type of growth may resemble it.

A clinician examines the surface, border, thickness and surrounding skin. If the appearance is uncertain or concerning, a small skin sample may be needed to identify the change rather than relying on appearance alone.

Arrange a routine dermatology visit for a persistent rough patch, especially if it sits on a sun-exposed area. Until it is assessed, avoid picking or filing it and reduce shoe friction over the spot. Photographing it beside a ruler can help you describe change. Protect the tops of the feet with suitable footwear or broad-spectrum sunscreen when they are exposed.

Treatment depends on whether there is one defined lesion or a wider field of sun damage. Options can include freezing a lesion, a prescribed topical medicine or light-activated treatment. The diagnosis, skin condition and healing needs of the foot guide the choice.

Seek prompt medical assessment if the area becomes a growing lump, thickens noticeably, bleeds without a clear injury, develops a persistent open sore or becomes increasingly painful. Redness spreading from a broken area, warmth, swelling, pus or fever can signal infection and also warrants timely care. These features do not establish the diagnosis, but they change how quickly the foot should be examined.

Ask whether the site and appearance fit actinic keratosis, whether dermoscopy or a biopsy would clarify it, and how the proposed treatment may affect walking, footwear and wound care. Also ask how to check the rest of your sun-exposed skin and when the treated foot should be reviewed.