Photopatch testing with an extended series of photoallergens: a 5-year study

We conducted a retrospective study (2003-07) evaluating the results of photopatch tests (PPTs) performed with an extended series with the objective of determining the main photoallergens in our region and whether they would be detected by a recently recommended baseline PPT series.

83 patients (58 females/25 males, mean age 54.8 years) were tested with a photoallergen series, and among these, 30 were also tested with a non-steroidal anti-inflammatory drug (NSAID) series, irradiated at D2 with 5 J/cm(2) ultraviolet A (UVA).

Thirty-six of 83 patients (43.3%) had at least one positive reaction, with 21 (25.3%) reacting in the photoallergen series. The main relevant reactions were as follows: 10 to ultraviolet filters (benzophenone-3 and benzophenone-4, 3 patients each), 7 to promethazine, and 2 to chlorpromazine. Twenty of 30 patients tested (70%) had a relevant positive PPT to an NSAID, 9 to piroxicam because of systemic photosensitivity, 8 to benzydamine from a topical gel or oral solution, and 2 to ketoprofen.

Our results are discordant with most recently published studies because of the particularities of the population studied and to regional prescribing habits. Therefore, apart from the recommended baseline series of photoallergens, other substances must be tested according to regional peculiarities.