All the Damage Without the Burn

Summary and Comment |
August 16, 2013

All the Damage Without the Burn

  1. Hensin Tsao, MD, PhD

A diagnosis of xeroderma pigmentosum should be considered in a child presenting with progressive lentigines on photoexposed sites, even without severe and prolonged sunburn.

  1. Hensin Tsao, MD, PhD

Patients with xeroderma pigmentosum (XP) have a considerably elevated risk for skin cancer due to a congenital defect in the repair of ultraviolet (UV) radiation–induced DNA damage. Mutations causing XP fall into eight complementation groups: XP-A to XP-G (classical XP) and XP variant (XP-V). Sunburn reactions have been considered critical to the development of XP in all patients. However, it is not clear whether individuals with differing complementation groups all have similar sunburn reactions.

These investigators examined sunburn reactions in XP patients and correlated reactions with complementation group. Using a newly developed sunburn severity score in 60 patients seen at an XP center in the U.K., the researchers found unusually high sunburn severity scores after minimal exposure in complementation groups XP-A, XP-D, XP-F, and XP-G compared with nonaffected controls. Patients with complementation groups XP-C, XP-E, and XP-V did not have significantly greater sunburn scores, but they did have significantly earlier diagnoses of skin cancer than those with elevated sunburn scores. The patients with severe sunburn also had a greater frequency of neurological abnormalities.


In earlier studies, some xeroderma pigmentosum patients were seen to have normal erythemal responses on phototesting. It is important to note that half of these patients had no history of severe sunburn but did have a more aggressive course of tumor development than those with severe sunburn. One major limitation of the study was that the sunburn severity score was based on responses to a questionnaire and not on empirical testing. These findings point to the complex relationship between sunburn and DNA damage, which could have important clinical implications for diagnosis and for development of sunscreens that protect against UV-induced skin cancers.

Editor Disclosures at Time of Publication

  • Disclosures for Hensin Tsao, MD, PhD at time of publication Consultant / advisory board Genentech; Quest Diagnostics; WorldCare Clinical Grant / research support NIH; Department of Defense; American Skin Association Editorial boards British Journal of Dermatology; Journal of the American Academy of Dermatology; Journal of Investigative Dermatology Leadership positions in professional societies American Academy of Dermatology (Chair, Skin Cancer and Melanoma Committee); American Board of Dermatology (Director)


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