While patients with photosensitivity disorders, such as polymorphic light eruption, chronic actinic dermatitis, solar urticaria and some forms of lupus erythematosus, are advised to minimise their sun exposure, it is not known how well they maintain their vitamin D status.
Researchers at the University of Manchester carried out a longitudinal prospective cohort study to compare year-round 25-hydroxyvitamin D levels, sun exposure behaviour and oral vitamin D intake in 53 photosensitive patients and 109 healthy controls.
The results showed that photosensitive patients followed photoprotective measures as recommended and therefore received lower doses of UVB during their leisure time, and were less likely to expose their skin to the sun and more likely to use sunscreen than healthy controls. Both groups were found to have low levels of oral vitamin D intake.
Photosensitive patients had lower levels of vitamin D, with 47% rated insufficient (<20ng/mL; 59nmol/L) or deficient (<10ng/mL; 25nmol/L) at the peak of summer, rising to 73% in mid-winter, compared with 9% and 32% for healthy controls in the summer and winter, respectively.
Photosensitive patients should therefore be given guidance on oral intake to increase their vitamin D levels.
Rhodes LE, Webb AR, Berry JL et al. Br J Dermatol August 11, 2014. doi: 10.1111/bjd.13325