Correspondence

Association between Actinic Keratoses and Potentially Photosensitizing Drugs

N Engl J Med 1999; 341:1474-1475November 4, 1999

Article

To the Editor:

Actinic (or solar) keratosis is a potential precursor of squamous-cell carcinoma of the skin. Its development is related to the cumulative exposure to ultraviolet radiation from the sun and the sensitivity of people to this radiation. Many drugs have photosensitizing effects,1-3 and some, such as psoralens4 and fluoroquinolones,5 augment photocarcinogenesis. We hypothesized that other photosensitizing drugs could also act in this way.

We studied 68 consecutive patients more than 60 years of age who were attending our dermatology clinic for various skin conditions other than actinic keratosis. We asked each patient if he or she had taken any drugs during the preceding five years. The drugs were classified as photosensitizing agents if they had been listed as such in published reports.1-3 The areas of the skin exposed to ultraviolet radiation were examined by an independent person for the presence of actinic keratoses, defined as rough, slightly erythematous macules. Among the 68 patients, 34 (22 men and 12 women; mean [±SD] age, 75±9 years) had at least one actinic keratosis, and 34 (11 men and 23 women; mean age, 72±8 years) did not. Thirty patients (44 percent, 17 men and 13 women) had taken at least one photosensitizing drug continuously for five years or more (Table 1Table 1Use of Photosensitizing Drugs by Patients with or without Actinic Keratoses.), whereas 38 patients (16 men and 22 women) had not. Among the 34 patients with actinic keratoses, 23 (68 percent) had taken one or more photosensitizing drugs, as compared with 7 of the 34 patients who had no actinic keratosis (21 percent, P<0.01 by the chi-square test).

These findings suggest that there is an association between long-term exposure to photosensitizing drugs and the development of actinic keratoses. Photosensitization below the threshold of overt photosensitivity reactions may nonetheless increase photodamage and lead to a higher incidence of actinic keratosis. Alternatively, the diseases for which therapy with photosensitizing drugs is needed could be related to increased photodamage or could induce photosensitivity. Although the results of this preliminary study need to be confirmed, sun-protective measures should be recommended to patients who are taking drugs with photosensitizing potential.

Marianne Placzek, M.D.
Bernadette Eberlein-König, M.D.
Bernhard Przybilla, M.D.
Ludwig-Maximilians-Universität, D-80337 Munich, Germany

5 References

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Citing Articles (3)

Citing Articles

1. 1

   Margaret R Karagas, Therese A Stukel, Virginia Umland, Maria M Tsoukas, Leila A Mott, Henrik T Sorensen, Annette O Jensen, Heather H Nelson, Steven K Spencer, Ann E Perry, Robert S Stern. (2007) Reported Use of Photosensitizing Medications and Basal Cell and Squamous Cell Carcinoma of the Skin: Results of a Population-Based Case–Control Study. Journal of Investigative Dermatology
   CrossRef

2. 2

   Marianne Placzek, Sabine Gaube, Urs Kerkmann, Klaus-Peter Gilbertz, Thomas Herzinger, Ekkehard Haen, Bernhard Przybilla. (2005) Ultraviolet B-Induced DNA Damage in Human Epidermis Is Modified by the Antioxidants Ascorbic Acid and D-α-Tocopherol. Journal of Investigative Dermatology 124:2, 304-307
   CrossRef

3. 3

   M. Placzek, U. Kerkmann, S. Bell, P. Koepke, B. Przybilla. (2004) Tobacco smoke is phototoxic. British Journal of Dermatology 150:5, 991-993
   CrossRef