Human leukocyte antigen system associations in Malassezia-related skin diseases.

BACKGROUND: The human leukocyte antigen system (HLA) is divided into two classes involved in antigen presentation: class I presenting intracellular antigens and class II presenting extracellular antigens. While susceptibility to infections is correlated with the HLA system, data on associations between HLA genotypes and Malassezia-related skin diseases (MRSD) are lacking. Thus, the objective of this study was to investigate associations between HLA alleles and MRSD. MATERIALS AND METHODS: Participants in The Danish Blood Donor Study (2010-2018) provided questionnaire data on life style, anthropometric measures, and registry data on filled prescriptions. Genotyping was done using Illumina Infinium Global Screening Array, and HLA alleles were imputed using the HIBAG algorithm. Cases and controls were defined using filled prescriptions on topical ketoconazole 2% as a proxy of MRSD. Logistic regressions assessed associations between HLA alleles and MRSD adjusted for confounders and Bonferroni corrected for multiple tests. RESULTS: A total of 9455 participants were considered MRSD cases and 24,144 participants as controls. We identified four risk alleles B*57:01, OR 1.19 (95% CI: 1.09-1.31), C*01:02, OR 1.19 (95% CI: 1.08-1.32), C*06:02, OR 1.14 (95% CI: 1.08-1.22), and DRB1*01:01, OR 1.10 (95% CI: 1.04-1.17), and two protective alleles, DQB1*02:01, OR 0.89 (95% CI: 0.85-0.94), and DRB1*03:01, OR 0.89 (95% CI: 0.85-0.94). CONCLUSION: Five novel associations between HLA alleles and MRSD were identified in our cohort, and one previous association was confirmed. Future studies should assess the correlation between Malassezia antigens and antigen-binding properties of the associated HLA alleles.

Pain perception in patients with hidradenitis suppurativa.

BACKGROUND: Pain is a prominent symptom of hidradenitis suppurativa (HS) and has been defined as a domain in the Core Outcome Set for the disease. Quality and intensity of pain is influenced by depression and anxiety, both of which are associated with HS. OBJECTIVES: To describe HS-related pain quantitatively and qualitatively; and to investigate how disease severity, depression and anxiety correlate with self-reported pain quality. METHODS: Pain perception was investigated using the McGill Pain Questionnaire. Symptoms of depression and anxiety were examined using the Hospital Anxiety and Depression Scale. Statistical analyses investigated differences in number of words chosen (NWC) and pain-rating index rank [PRI(R)] in patients with severe disease and in patients with depression/anxiety. RESULTS: A total of 138 patients with HS were recruited in an outpatient clinic (October 2017-March 2018). Patients presented a median NWC of 11·5 and a PRI(R) of 59·0%. Most common descriptors were 'shooting' (83%), 'itchy' (79%) and 'blinding' (75%). Patients with depression or anxiety presented significantly higher PRI(R)s [depressed 65% vs. non-depressed 57% (P = 0·015); anxious 65% vs. nonanxious 57% (P = 0·004)]. Patients with involvement of three or more HS regions vs. those with fewer than three involved regions exhibited a significantly higher NWC (13 vs. 8; P = 0·048). CONCLUSIONS: HS-related pain includes nociceptive and neuropathic pain, and perception appears to be influenced by disease severity, anxiety and depression. A multimodal pain management strategy may be the most appropriate; however, more detailed studies are necessary to define recommendations on pain management. What's already known about this topic? Pain is a core outcome domain hidradenitis suppurativa. Few studies have addressed this significant clinical problem. What does this study add? This study suggests that HS pain comprises both nociceptive and neuropathic pain. Pain appears associated to depression, anxiety and severity of the disease.