INTRODUCTION
The electromagnetic spectrum is the range of all possible frequencies of electromagnetic radiation and is arranged based on wavelength, from shortest to longest (gamma rays, X-rays, ultraviolet (UV) rays, visible light, infrared (IR), microwaves, and radio waves, respectively). The visible portion of the electromagnetic spectrum is defined as the portion of electromagnetic radiation visible to the human eye, which corresponds to wavelengths from 400 to 700 nanometers (nm).1,2 The impact of UV radiation on skin pigmentation has been well-established and its association with cutaneous disease, which range from aging and chronic actinic photo-damage to both non-melanoma and melanoma carcinogenesis, has been described in the literature.2-8 While most of the attention with respect to skin darkening is focused on the effect of the UV region of the solar spectrum, the effect of visible radiation has received very little attention. However, solar radiation reaching the earth’s surface contains 12 to 14 times more visible radiation than UV.6 In this report we describe a case of erythema and pain that resulted from irradiation of UV-naïve skin with visible LED light devoid of UV or IR light in a patient with Fitzpatrick type II skin.
CASE REPORT
A 24-year-old healthy woman with Fitzpatrick type II skin presented to our department to participate in a clinical study. The clinical study investigated the effects of two different sources of visible light, light emitting diode (LED) and halogen incandescent, on the cutaneous pigmentary response in individuals with Fitzpatrick skin types I-VI. The study was reviewed and approved by the Institutional Review Board at New York University School of Medicine.Past medical history included hyperthyroidism treated with levothyroxine. She was not taking any other medications or over-the-counter supplements. A history determined that the patient had a Fitzpatrick type II skin score. A focused skin examination yielded no cutaneous findings (Figure 1a, 1d).As part of the study protocol, the subject underwent visible light irradiation utilizing an LED light source and a halogen incandescent light source (Mi LED-US-A2 and Fiber-Lite Mi 150F, Dolan-Jenner Industries, Boxborough, MA, respectively). The subject was to undergo 7 different irradiation spots with either light source, with incrementally increased dosage in each
