The following signs and symptoms should be investigated by a general practitioner:

• any new or changing skin lesions or lesions that do not respond to treatment
• a rapidly growing skin lesion that remains unresolved after one month.

SCCs arise on the background of sun-damaged skin characterised by actinic keratoses. The following symptom should be investigated for SCC:

• induration (thickening) or tenderness in the erythematous base of a scaling lesion.

The following signs and symptoms should be investigated for BCC:

• a dome-shaped skin lesion
• a pink or red scaly patch
• waxy or pearly hard skin-coloured lesion
• a sore that will not heal or with blood vessels.

The presence of multiple signs and symptoms, particularly in combination with other underlying risk factors, indicates an increased risk of keratinocyte cancer.