Background: Pityriasis versicolor is a superficial fungal disease with a world-wide distribution, but there are few available studies on its prevalence in the general population.
Objectives: To assess the prevalence of pityriasis versicolor in a representative sample of young Italian sailors, evaluating the influence of habits and risk factors in the affected individuals.
Methods: Young cadets (n = 1024: 975 men and 49 women, mean age 22 years) of the Italian Navy Petty Officers' School in Taranto were consecutively examined by the same observer. The diagnosis of pityriasis versicolor was based on clinical picture and/or Wood's lamp examination. All the subjects filled in a questionnaire about sport practice, swimming pool attendance, marching, presence of hyperhidrosis and a positive clinical history of pityriasis versicolor in the past. The affected individuals were also asked if they were aware of their skin lesions. Differences between answers of affected and unaffected subjects were tested by Fisher's exact P-value test, and odds ratios were calculated.
Results: Pityriasis versicolor was diagnosed in 22 subjects (2.1%), all men, of whom 15 (68%) were not aware of their condition. No statistical association was found between active pityriasis versicolor and sport practice, swimming pool attendance, marching or presence of hyperhidrosis. A significant association [odds ratio 8.7 (95% confidence interval 3.3-21.5); Fisher's exact P-value test P < 0.01] was documented between active pityriasis versicolor and a previous clinical history of pityriasis versicolor.
Conclusions: The prevalence of pityriasis versicolor in this sample of young Italian sailors was not high, in agreement with the available surveys performed in the general population in temperate climates. Many affected subjects were not aware of their condition. The only important factor associated with pityriasis versicolor was a previous history of pityriasis versicolor. This observation could confirm the hypothesis that constitutional factors, e.g. seborrhoea and chemical constitution of sebum, may play a crucial role in temperate climates, leading to relapsing forms of this superficial mycosis.