Does nickel make you itch? Skin allergies may reduce risk of cancer by ‘priming immune system
Skin allergies can cause immense grief to sufferers but now scientists have some good news – the itchy condition could also help ward off cancer. Danish researchers found that those who reacted to common irritants such as perfume or nickel were less likely to develop three different cancers.
This may be because such contact allergies, where the body falsely believes it is under attack, help prime the immune system to fight off other threats. The team, led by Dr Kaare Engkilde, of Copenhagen University Hospital, studied a database of just under 17,000 adults who all undertook patch tests for common contact allergens between 1984 and 2008.
They found just over one in three or around 6,000 people, tested positive for at least one contact allergy. They then compared these results with data from the Danish Cancer Registry.
The researchers found there were significantly lower rates of breast and non-melanoma skin cancer in both sexes among those with contact allergies. There were also lower rates of brain cancer among women. Previous research has found people with allergies to pollen and house dust mites may be protected against the disease. These findings back up the ‘immunosurveillance hypothesis,’ which holds that people with allergies are less likely to develop cancer because their immune systems are super responsive, say the authors.
‘Perhaps there’s some protective function and therefore, the immune system is perhaps more likely to fight off certain things, including cancers,’ Dr Clifford Basset at NYU Langone School of Medicine told ABC News.
The analysis also picked up higher rates of bladder cancer found among those with contact allergies, which might be the result of higher levels of chemical metabolites accumulated in the blood, they suggest. Writing in BMJ Open, the authors caution that it is too early to draw definitive conclusions about cause and effect. They said further research will be needed to adjust for other risk factors such as social class and smoking.