Washington: Common contact allergies may be a blessing in disguise, as a new study has found that those who are afflicted by the itchy rashes appear to have a reduced risk of various cancers.
Researchers at the National Allergy Research Centre at Copenhagen University Hospital Gentofte in Denmark found that people who develop rashes when their skin comes into contact with certain metals or chemicals have a "significantly lower" risk for certain cancers such as breast and non-melanoma skin cancer compared to those without the immune system disorder.
For their study, they focused on nearly 17,000 adults with contact allergies which generally develop win 24 hours on the area that touched the allergen, as reported.
About one-third of the participants tested positive for at least one contact allergy, with women more likely to test positive (41 percent) than men (26 percent). The participants were tested between 1984 and 2008.
The researchers then examined cancer cases among the study participants over the long term.  The results, published in the journal BMJ Open, showed that men and women with contact allergies had significantly lower rates of breast cancer and non-melanoma skin cancer.
The study also showed that women with such allergies had lower rates of brain cancer compared with women without the disorder, though that was not statistically significant.

However, the researchers found that both men and women with contact allergies had higher rates of bladder cancer, which "could be due to accumulations of chemical metabolites in the bladder". The lower rates of brain, breast and non-melanoma skin cancer among those with contact allergies may be the result of how their immune systems function.
The new findings "might support" the theory that people with contact and other allergies had hyperactive immune systems primed to detect and stamp out tumours more quickly as they formed, the researchers wrote.
However, the researchers cautioned that the results showed a correlation between contact allergies and lowered rates of some cancers, but do not mean that one caused the other.