Blessmann Weber M, Sponchiado de Avila L G, Albaneze R, Magalhães de Oliveira O L, Sudhaus B D, Cestari T Ferreira
School of Medicine, Lutheran University of Brazil (ULBRA), Canoas, RS.
J Eur Acad Dermatol Venereol. 2002 Sep;16(5):463-8. doi: 10.1046/j.1468-3083.2002.00494.x.
The aetiology of pityriasis alba (PA), a common dermatosis in childhood, is still controversial. The objective of this study was to assess the possible aetiopathogenic factors of this disease in infants.
Forty-four patients with PA and 31 healthy children were examined and compared. Personal hygiene habits, sun exposure, presence of Staphylococcus aureus in nasal fossae and presence of major or minor signs of atopy were assessed during anamnesis and physical examination. Susceptibility to ultraviolet (UV) B radiation was measured by the onset of a contact hypersensitivity reaction to diphenylcyclopropenone in individuals sensitized in previously irradiated areas.
The prevalence of PA was higher in individuals with darker skin, in high phototype categories, as well as in males. The number of daily baths and sun exposure between 10.00 h and 15.00 h were significantly higher in the PA group when compared with controls (P = 0.03 and P = 0.0015, respectively). The presence of atopy signs was more common in pityriasis patients (P = 0.002). Susceptibility to UVB radiation was 29.6% in the PA group vs. 29.0% in the control group; nevertheless, important differences were found after stratification in order to control possible confounding factors. The presence of S. aureus in the nostrils was equal in both groups.
Our results confirm that PA, in our population, is more prevalent in males and in individuals in higher phototype categories. In those with inadequate personal hygiene and sun exposure habits the disease is more accentuated, demonstrating that the xerosis presenting in individuals with atopic diathesis is an important element in the development of the disease. S. aureus is not an important aetiopathogenic factor in PA. Susceptibility to UVB becomes important when related to the patient's phototype.
白色糠疹（PA）是儿童常见的一种皮肤病，其病因仍存在争议。本研究的目的是评估婴儿期该疾病可能的病因学因素。
对44例PA患者和31名健康儿童进行检查并比较。在问诊和体格检查过程中，评估个人卫生习惯、日晒情况、鼻窝中金黄色葡萄球菌的存在情况以及特应性的主要或次要体征。通过对先前照射区域致敏的个体对二苯环丙烯酮的接触性超敏反应的发生情况来测量对紫外线（UV）B辐射的敏感性。
PA在皮肤较黑、光型类别较高的个体以及男性中患病率更高。与对照组相比，PA组每日洗澡次数以及10:00至15:00之间的日晒时间显著更高（分别为P = 0.03和P = 0.0015）。特应性体征在白色糠疹患者中更为常见（P = 0.002）。PA组对UVB辐射的敏感性为29.6%，对照组为29.0%；然而，为控制可能的混杂因素进行分层后发现了重要差异。两组鼻孔中金黄色葡萄球菌的存在情况相同。
我们的结果证实，在我们的人群中，PA在男性和光型类别较高的个体中更为普遍。在个人卫生习惯和日晒习惯不良的人群中，该疾病更为严重，表明特应性素质个体出现的皮肤干燥是该疾病发展的一个重要因素。金黄色葡萄球菌不是PA的重要病因学因素。当与患者的光型相关时，对UVB的敏感性变得重要。
