Spectrum of idiopathic photodermatoses in a Mediterranean country

Idiopathic photodermatoses are considered to be common disorders in the population of northern latitude countries, presumably because of the dominance of more "sun-sensitive" individuals with a light-skinned complexion. The incidence of these disorders in the Mediterranean or tropical countries is often under-appreciated because of the higher degree of perennial presence of sunlight and the prevalence of darker skin-type individuals who are seemingly more resistant to the development of sun sensitivity.

We performed a retrospective, chart-based review of all patients who were diagnosed with idiopathic photodermatoses at a photodermatology referral center in Athens, Greece, during a period of 10 years. Our aim was to assess the pattern of idiopathic photosensitivity disorders in a Mediterranean country and to determine their epidemiological, clinical, and photobiological profile.

A total of 310 patients were referred to our center with symptoms of photosensitivity. One hundred and forty-six patients (47.0%) were diagnosed with an idiopathic photosensitivity disorder by means of history, clinical examination, biochemical screening, histology, and phototesting. The most prevalent disorder was polymorphous light eruption, which was diagnosed in 95 patients (65.0%) of our cohort. Chronic actinic dermatitis occurred in 15 patients (10.2%), solar urticaria in 26 patients (17.8%), actinic prurigo in three patients (2.0%), hydroa vacciniforme in one patient (0.6%) and juvenile spring eruption in six patients (4.1%).

Compared with the results of other studies, the prevalence of idiopathic photodermatoses appears to have a similar trend to that of higher latitude countries. Distinct features in our series include the higher incidence of idiopathic photosensitivity in patients with a fair-skinned complexion (skin types II-III) and the frequent appearance of photo-induced eruptions during sunny weather breaks in the winter period.