Differences in sun exposure habits between self-reported skin type and ultraviolet sensitivity measured by phototest

Background: Traditionally, classification of skin reactivity to ultraviolet (UV) light is based on self-estimation of tendency to burn and tan (Fitzpatrick's classification). Although widely accepted, the model has shown to correlate poorly with actual UV sensitivity, measured by phototest. The aim of the present study was to investigate how self-estimated skin type, according to Fitzpatrick, and actual UV sensitivity measured by phototest correlate with sun exposure and protection. Methods: One hundred and sixty-six voluntary patients visiting their general practitioner for investigation of suspicious skin tumours were recruited for the study, and filled out a questionnaire, mapping sun habits and sun protection behaviour, based on five-point Likert responses. The patients reported their skin type (I-VI) according to Fitzpatrick, and a phototest was performed to determine the minimal erythema dose. Results: For most of the questions, high self-estimated UV sensitivity, according to Fitzpatrick, appeared to be associated with a higher level of sun avoidance/protection (P < 0.05). For actual UV sensitivity, however, the difference in response distribution was only significant for sunscreen use, and did not show a similar apparent association related to the degree of UV sensitivity. Conclusion: Self-estimated skin UV sensitivity, according to Fitzpatrick's classification, appears to be a stronger predictor of sun exposure and protection than actual UV sensitivity measured by phototest.