Can sun-damaged skin cause keratoacanthoma?

A keratoacanthoma often begins as a firm, round bump and may enlarge quickly before developing a central keratin-filled plug or crater. It commonly occurs on exposed skin, including the face, ears, backs of the hands, and forearms. Chronic ultraviolet damage may contribute to the abnormal growth, but not every lump in sun-damaged skin is a keratoacanthoma. Some lesions can resemble squamous cell skin cancer, so a clinician may need a biopsy to distinguish them.

Arrange a dermatology appointment soon for a new lump that grows noticeably, feels firm, crusts, or develops a central plug. Do not squeeze, shave, or burn it at home. Photographing it beside a familiar object can help you describe change, but it does not replace examination. Use shade, protective clothing, and sunscreen on exposed skin while waiting.

Seek prompt care if the lump is enlarging rapidly, bleeding, ulcerated, increasingly painful, or interfering with an eyelid, ear, nose, or lip. A lesion that changes over days or weeks should not be watched indefinitely because its appearance can overlap with a more serious skin tumour.

Does this need a biopsy? Could it be squamous cell skin cancer or an infection? What treatment is suitable for its site, and what signs should make me return sooner?