First Disease Map of Eczema Links Unveiled Using NHS Patient Records

Analyzing patient health care notes recorded during millions of medical appointments at GPs and hospitals across England has allowed researchers at the London School of Hygiene & Tropical Medicine (LSHTM) to map the entire spectrum of diseases linked to atopic eczema for the first time. They found that patients diagnosed with atopic eczema at some point in their life were more likely to also be diagnosed with eye conditions compared with those who did not have an eczema diagnosis. These included not just allergic conjunctivitis but also more serious conditions known to permanently affect vision, such as keratoconus (twice as likely) and cataracts (1.6 times more likely). Strong associations were also identified with inflammatory bowel diseases. The association with Crohn's disease in particular was persistently strong across the several different types of analyses performed in the study, with a Crohn's disease diagnosis 1.7 times more likely for those also diagnosed with eczema. Eczema, also known as atopic dermatitis, is a common skin condition that affects approximately 1 in 5 children and 1 in 10 adults in the U.K. It has well-established connections with the development of other allergy-based (atopic) diseases but there is less certainty surrounding its associations with other diseases. The study, published in Nature Communications, analyzed anonymized patient health care records from both GPs and hospitals in England between 1997 and 2023. Using the anonymized data collected from GP practices, which are the usual first point-of-contact for patients in the U.K. health care system and where almost all eczema cases are managed, the team first analyzed how many patients had been diagnosed with atopic eczema (3 million versus 14 million without a diagnosis). The team then analyzed those patients' linked anonymized hospital records, to uncover associations between eczema and other conditions that arose during a 25-year follow-up period. As expected, the team found strong associations with allergy-based conditions already known to be associated with atopic eczema, including asthma, food allergies and hay fever. In comparison, awareness of the connections found with eye conditions and inflammatory bowel disease in the study is limited, indicating a need for guidance for GPs and dermatologists on monitoring other potential conditions and making referrals to other departments. Dr. Julian Matthewman, Assistant Professor at LSHTM and lead author of the study, said, "We believe this may be the first study to comprehensively map the diseases associated with eczema. "Eczema can affect people of all ages, and can be extremely painful and distressing for many patients. Through mapping and uncovering diseases associated with eczema that may not be widely known, we want to equip patients with the knowledge to ask more questions, and provide health care practitioners with a bigger picture to encourage better communication between departments. "We know that patients living with long-term health conditions can often experience delays in getting the treatment they need or may need to attend numerous health care appointments to reach a diagnosis. We hope that our comprehensive, real-world evidence can now assist health care in prioritizing resources where they can be most effective for patients." The team conducted more than 60,000 analyses, which looked at more than 2,000 different health conditions. While associations with other diseases outside eye conditions and inflammatory bowel disease were also found, it was, reassuringly, still generally rare for eczema patients to be diagnosed with these conditions. As the study only looked at electronic health records and is observational, the team say it does not prove or disprove that eczema directly causes these conditions. It may also be possible that some patients were misdiagnosed with eczema, or that medical records were incomplete or inaccurate.