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Sunscreen applied at ≥ 2 mg cm −2 during a sunny holiday prevents erythema, a biomarker of ultraviolet radiation‐induced DNA damage and suppression of acquired immunity
Author(s) -
Narbutt J.,
Philipsen P.A.,
Harrison G.I.,
Morgan K.A.,
Lawrence K.P.,
Baczynska K.A.,
Grys K.,
RogowskiTylman M.,
OlejniczakStaruch I.,
Tewari A.,
Bell M.,
O'Connor C.,
Wulf H.C.,
Lesiak A.,
Young A.R.
Publication year - 2019
Publication title -
british journal of dermatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.304
H-Index - 179
eISSN - 1365-2133
pISSN - 0007-0963
DOI - 10.1111/bjd.17277
Subject(s) - erythema , dermatology , sun protection factor , sunburn , medicine , skin cancer , ultraviolet radiation , chemistry , cancer , radiochemistry
Summary Background Sun protection factor ( SPF ) is assessed with sunscreen applied at 2 mg cm −2 . People typically apply around 0·8 mg cm −2 and use sunscreen daily for holidays. Such use results in erythema, which is a risk factor for skin cancer. Objectives To determine (i) whether typical sunscreen use resulted in erythema, epidermal DNA damage and photoimmunosuppression during a sunny holiday, (ii) whether optimal sunscreen use inhibited erythema and (iii) whether erythema is a biomarker for photoimmunosuppression in a laboratory study. Methods Holidaymakers ( n = 22) spent a week in Tenerife (very high ultraviolet index) using their own sunscreens without instruction (typical sunscreen use). Others ( n = 40) were given SPF 15 sunscreens with instructions on how to achieve the labelled SPF (sunscreen intervention). Personal ultraviolet radiation ( UVR ) exposure was monitored electronically as the standard erythemal dose ( SED ) and erythema was quantified. Epidermal cyclobutane pyrimidine dimers ( CPD s) were determined by immunostaining, and immunosuppression was assessed by contact hypersensitivity ( CHS ) response. Results There was no difference between personal UVR exposure in the typical sunscreen use and sunscreen intervention groups ( P = 0·08). The former had daily erythema on five UVR ‐exposed body sites, increased CPD s ( P < 0·001) and complete CHS suppression (20 of 22). In comparison, erythema was virtually absent ( P < 0·001) when sunscreens were used at ≥ 2 mg cm −2 . A laboratory study showed that 3 SED from three very different spectra suppressed CHS by around ~50%. Conclusions Optimal sunscreen use prevents erythema during a sunny holiday. Erythema predicts suppression of CHS (implying a shared action spectrum). Given that erythema and CPD s share action spectra, the data strongly suggest that optimal sunscreen use will also reduce CPD formation and UVR ‐induced immunosuppression.