Background: Hyperhidrosis is defined as excessive sweating which can be primary or secondary. Data about the prevalence of primary hyperhidrosis are scarce for northern Europe. Objective: Our aim was to investigate the prevalence of hyperhidrosis focusing on its primary form and describe the quality of life impairments for the affected individuals. Methods: Five thousand random individuals aged 18-60 years in Sweden were investigated. The individuals' addresses were obtained from Statens personadressregister, SPAR, which includes all persons who are registered as resident in Sweden. A validated questionnaire regarding hyperhidrosis including the Hyperhidrosis Disease Severity Scale (HDSS) and 36-item Short Form (SF-36) health survey was sent to each individual. The participants were asked to return the coded questionnaire within 1 week. Results: A total of 1,353 individuals (564 male, 747 female and 42 with unspecified gender) with a mean age of 43.1 ± 11.2 years responded. The prevalence of primary hyperhidrosis was 5.5%, and severe primary hyperhidrosis (HDSS 3-4 points) occurred in 1.4%. Secondary hyperhidrosis was observed in 14.8% of the participants. Our SF-36 results showed that secondary hyperhidrosis causes a significant (p < 0.001) impairment of both mental and physical abilities while primary hyperhidrosis impairs primarily the mental health (p < 0.001). Conclusion: Hyperhidrosis affects individuals in adolescence as a focal form while occurring as a generalised form with increasing age. Further, the prevalence of primary hyperhidrosis described in our study is comparable to other studies from the western hemisphere. While secondary, generalised hyperhidrosis impairs both physical and mental aspects of life, primary hyperhidrosis, with the exception of severe cases, mainly affects the mental health.

Epigenetic modifications by DNA methylation are associated with a wide range of diseases. Previous studies in psoriasis have concentrated on epigenetic changes in immune cells or in total skin biopsies that include stromal-associated changes. In order to improve our understanding of the role of DNA methylation in psoriasis, we sought to obtain a comprehensive DNA methylation signature specific for the epidermal component of psoriasis and to analyze methylation changes during therapy. Genome-wide DNA methylation profiling of epidermal cells from 12 patients undergoing narrow-band UVB phototherapy and 12 corresponding healthy controls revealed a distinct DNA methylation pattern in psoriasis compared with controls. A total of 3,665 methylation variable positions (MVPs) were identified with an overall hypomethylation in psoriasis patient samples. DNA methylation pattern was reversed at the end of phototherapy in patients showing excellent clinical improvement. Only 7% of phototherapy-affected MVPs (150 out of 2,108) correlate with nearby gene expression. Enrichment of MVPs in enhancers indicates tissue-specific modulation of the transcriptional regulatory machinery in psoriasis. Our study identified key epigenetic events associated with psoriasis pathogenesis and helps understand the dynamic DNA methylation landscape in the human genome.

Lichen planus (LP) is a chronic mucocutaneous disease with unknown cause. Patients with LP often have both oral and genital lesions, but these conditions are often considered as separate diseases and treated accordingly. To find out which genes are differently expressed in mucosal LP compared to normal mucosa and establish whether oral and genital LP are in fact the same disease, whole genome expression analysis was performed on epithelium from 13 patients diagnosed with oral and/or genital LP and normal controls. For confirmation of keratin 4 and corneodesmosin expression, quantitative reverse-transcription PCR and immunohistochemistry were used. Many genes involved in epithelial development and differentiation are differently expressed in epithelium from LP compared to normal epithelium. Several of the differentially expressed genes are common for oral and genital LP and the same biological processes are altered which supports the fact that oral and genital LP are manifestations of the same disease. The change in gene expression indicates that differentiation is altered leading to changes in the epithelial barrier.

Centralised contact tracing, exploring the sexual history for at least 12 months back in time, shows good results. Combined with screening of certain risk groups it is probably one effective way of preventing C trachomatis infections. Preventing C trachomatis by primary prevention such as information and counselling is, however, still of great importance.

Even if no specific LP-associated miRNA profile was found, data clearly indicate that miRNAs could play a role in the earlier phases of lichen planus.