Cutaneous squamous cell carcinoma (cSCC) can develop de novo or from pre-existing chronic actinic damage, although the probability and speed of transition from actinic keratosis to cSCC is highly variable. The occurrence of cSCC is related to chronic UV exposure, particularly occupational exposure. Risk factors include fairer skin, significant exposure to sunlight or PUVA. Incidence is also significantly increased in patients who are immunosuppressed. All patients with suspected cSCC should be referred via the two-week wait pathway to dermatology.