Pigmented naevi and sun protection behaviour among primary and secondary school students in an Eastern Hungarian city.

BACKGROUND: The most important risk factors for malignant melanoma are skin type I or II, large number of atypical naevi and a history of sunburn in childhood and adolescence. METHODS: A cross-sectional study was performed to assess skin type, number of pigmented lesions and sun protection behaviour in 1157 12- to 19-year-old Hungarian students at 20 primary and secondary schools in Debrecen, Hungary. After receiving dermatological training, 18 school doctors examined the students' skin. A questionnaire was completed by the students with the assistance of their parents about sun protection, sunburns and the use of sunbed. Data from 612 questionnaires were evaluated. RESULTS: Based on the doctors' evaluation, most of the pupils were classified as having skin type II and majority of them had 5-20 naevi, particularly on the trunk. Based on the student's response, 5.2% purposely sunbathed daily, 10.1% did not use any form of sun protection, 32.2% wore sun-protective clothing and 65.7% applied sunscreen generally. 6.9% used sunbed, and 74.0% previously experienced serious sunburn at least once. Indoor tanning statistically correlated with the number of melanocytic naevi. CONCLUSION: A high prevalence of sunburn was reported by the students and some of them did not apply any sun protection methods but used sunbed at a critical age for developing melanoma at a later time. These data highlight the importance of educating children and parents about appropriate sun protection.

Photosensitivity skin disorders in childhood.

Photosensitivity in childhood is caused by a diverse group of diseases. It usually indicates idiopathic photodermatoses, first of all polymorphic light eruption. It may be an early symptom of genetic disorders such as porphyria or very rare genophotodermatoses. Photosensitivity secondary to topical or systemic external agents as well as photoexacerbated dermatoses is not so frequent in childhood. Here we present our experience with childhood photosensitivity skin diseases collected over a 40-year period.

Low concentrations of formaldehyde induce DNA damage and delay DNA repair after UV irradiation in human skin cells.

Long-term occupational exposure to formaldehyde (FA) increases the risk for nasopharyngeal squamous cell carcinoma. As the skin is also in contact with FA by environmental exposure, we tested the genotoxic properties of appropriate low concentrations (<100 microM) of FA on cultured keratinocytes and fibroblasts of human skin. The initial DNA damage was assessed by comet assay. The induction of DNA protein crosslinks was measured by the ability of FA to reduce DNA migration induced by methyl-methane-sulfonate. Upon 4 h of exposure to FA, significant (P < 0.05) crosslink formations were observed in fibroblasts (50 microM FA) and in keratinocytes (25 microM FA). Upon 8 h of exposure to FA (25 microM FA), significant crosslink formations were observed in both the cell types. FA is known to inhibit different DNA repair pathways. Therefore, we studied the effect of FA on UV-induced repair. Human keratinocytes and fibroblasts exposed to 10 microM FA prior to UV irradiation showed disturbed repair kinetics after UVC and UVB, but not after UVA irradiation. Single-strand breaks (SSBs) derived from nucleotide excision repair disappeared 6 h after solely UVC (3 mJ/cm2) or 3 h solely UVB (30 mJ/cm2) exposure in both the cell types. In the presence of FA, SSBs were still present at these time points containing a reference to a delay in DNA resynthesis/ligation. FA at a concentration not inducing micronuclei (12.5 microM) caused significant increase of UVC-induced (4 mJ/cm2) chromosomal damage. Proliferation of keratinocytes and fibroblasts was in parallel to observed DNA damages. In conclusion, our data suggest that environmental exposure to FA may contribute to UV-induced skin carcinogenesis.