The over-the-counter creams, gels and patches used by athletes and other pain sufferers on sore muscles and joints for warmness and coolness can experience burning pain or blistering.
The injuries are rare, but the FDA advises those who experience them to seek medical care. There have been 43 cases reported to the FDA's adverse events database after use of the products containing higher amounts of active ingredients menthol (3 percent) and methyl salicylate (10 percent). There were a few cases involving capsaicin.
Consumers have reported the injuries after just one application within 24 hours.
"There's no way to predict who will have this kind of reaction to a topical pain reliever for muscles and joints," says Dr. Jane Filie, a medical officer in FDA's Division of Nonprescription Regulation Development, in a statement.
The FDA advises consumers not to use the products on damaged or irritated skin and not to apply bandages or heating pads or other forms of heat. Officials say to avoid contact with eyes or skin in the mouth, nose or genitals. They also say to watch for signs of blistering or burning and seek medical attention if they occur.