Seasonal Variation in Hand and Upper Limb Soft Tissue Infections.

Background: Hand and upper limb soft tissue infections result in significant disability and loss of productivity. Many infections have been shown to follow a seasonal variation, however little is known about this is the context of upper limb soft tissue infections. We aimed to evaluate seasonal variation in acute bacterial, hand and upper limb skin and soft-tissue infections, and correlate findings with key environmental variables. Methods: Hand and upper limb soft tissue infection cases from 2006-2016 were retrieved from a single UK center. Cases were reviewed for microbiology culture and sensitivity. Correlation between cases and season, temperature and humidity was assessed. Results: 206 cases were identified for inclusion. Specimens were sent for microbiology in 76.4% of cases. Of these 78.9% were culture positive, 47.6% exhibited antibiotic resistance and 16.9% were multi-resistant. There was a significant difference between season and culture positive cases, with significantly more culture positive cases in the summer vs. winter on post-hoc analysis (p = 0.004). There was a significant positive correlation between higher temperatures and number of culture positive cases (r = 0.75). There was no significant correlation between temperature and antibiotic resistance (r = 0.5) or between humidity and culture positive cases (r = -0.42). Conclusions: This study demonstrates a seasonal variation in hand and upper limb infections, with a significant correlation between infection rates and ambient temperature. Appreciating seasonal variability of these infections could prove beneficial for surgical planning, public health recommendations and antibiotic guidelines. However, further international data is needed to understand potential mechanisms involved.