Crohn’s disease risk linked to hidradenitis suppurativa

An Australian expert says it makes 'perfect sense', but there are steps patients and doctors can take.

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Paediatric patients with hidradenitis suppurativa are at higher risk of developing Crohn disease, new research has found. 

The study, published in JAMA Dermatology, found the prevalence ratio of Crohn’s disease was almost five times higher among patients with HS than in the control group. 

The study used data from the IBM Explorys database, a health system research platform with electronic health records from more than 40 US health care networks. The study population included almost 3000 children (median age 17 years) with HS, and 222,000 (median age 16 years) without. 

Crohn’s disease was prevalent in 0.69% of patients with HS and 0.17% of children in the control group. 

“Findings of this study suggest an association between CD and HS in paediatric patients,” the authors wrote. “However, the low absolute prevalence of CD in this group is reassuring and should be taken into context when counselling patients.” 

Leading Australian HS expert, Associate Professor Erin McMeniman, a specialist dermatologist at the Princess Alexandra Hospital and chair of the Queensland Faculty of Dermatology, said it was an interesting paper but needed to be considered as part of a bigger picture. 

“I welcome any research into furthering our understanding of this terrible disease, and this is an important question of association for our paediatric patients,” she said.  

The link made “perfect sense” due to the disordered immune system, she said. 

“We know they have similar immune pathways, T cell, cytokines and have an overlap in effective biologic treatments,” she said. 

She said the “significantly higher” risk of Crohn’s disease in HS patients was important for doctors to be aware of, however she did not think it meant every child with HS needed investigation. 

“It probably does mean every child with HS should be questioned about GI symptoms of CD/IBD such as pain, bowel habit changes and blood/mucus in bowel motions,” she said. 

“I do not think every child with HS needs referral for colonoscopy or even to have faecal calprotectin.” 

Professor McMeniman said it was important to note the researchers found that in patients with HS, 58% were obese, compared to group without HS, in which 23% were obese. 

“While this does not prove causation it is in keeping with adult findings,” she told The Medical Republic.  

“We do know that once a child develops HS, exercise can be painful and can directly flare their lesions, so in my opinion this is further support for the importance of all children aiming for a health body weight, good diets and regular exercise.” 

She said patients and their carers should be aware and empowered to tell health care providers about symptoms such as bowel changes and get screening for IBD if warranted. 

“A very important point all doctors treating children with HS need to be aware of is the importance of that child never starting smoking, avoiding passive smoking and never getting addicted,” said Professor McMeniman. 

“I tell all my paediatric patients about this; it is the single most important lifestyle factor they can avoid to try to keep their disease as mild as is possible.” 

It was also important to be aware that HS was an autoimmune inflammatory disease and patients could be at greater risk of other similar immune diseases.  

“Patients have suffered delayed diagnosis, misdiagnosis and what has been all too often a painful journey of seeing more than five doctors with symptoms of HS before they are properly diagnosed,” she said. 

Professor McMeniman said treatment for HS had come a long way, but there were still too many barriers to timely diagnosis. 

She has been treating HS patients for many years and has been involved in the development of a special interest clinic with a multi-disciplinary team that receives referrals from around Queensland and even interstate.  

She said the disease was a lot more common than most people realised, affecting close to one in 100 people. HS is associated with several other conditions, including polycystic ovarian syndrome, inflammatory bowel disease, metabolic syndrome, diabetes mellitus type 2 and depression. It is estimated that 30% to 40% of patients have a family history of HS.