The effects of Elidel and Protopic on the developing immune system in children is not known. In clinical studies with Elidel, children under two had a higher rate of upper respiratory infections than those treated with a placebo cream.

As the long-term safety of the creams remains questionable, the FDA advises that they should be used for just short periods of time and only by patients who don’t respond with or are intolerant of other treatments. Children and adults with compromised immune function should also avoid these creams, says the American regulatory body.

As well as a cream, tacrolimus can also be taken in a pill or by injection to prevent liver or kidney transplant rejection. Marketed as Prograf, it can cause skin cancer and lymphomas in people by suppressing normal immune defences. The higher the dose and longer the treatment, the higher the cancer risk (www.fda.gov/cder/drug/advisory/elidel_protopic.htm).