The Food and Drug Administration has ordered that "black box" warnings be placed on two popular drugs used to treat the skin condition eczema. The black box warning is the strongest type of warning that can be placed on medication. The FDA says that Protopic and Elidel may increase the risk of cancer.

The medications are usually applied topically through a cream. A recent study on animals revealed the increased cancer risk while approximately two dozen human cases of cancer have been discovered that may be linked with the drugs.

Now, the FDA is recommending that Elidel and Protopic only be given to people who don't respond to other treatments and only be prescribed by doctors for short-term use. It is also suggested that these medications should never be used by children under two years of age.

The FDA announced that the drug companies were cooperating in additional studies. 'The manufacturers of the products have agreed to conduct research to determine whether there is an actual risk of cancer in humans, and, if so, its extent,' the FDA said Thursday.

There was no word as to when additional test results would be made available.