You may be allergic to your shampoo and not even know it. Many shampoos and skin conditioners contain an ingredient that can cause eczema. As many as one in 50 people may be allergic to the chemical, according to researchers at the University of Gothenburg, Sweden.
Eczema can cause a lot of different skin conditions, including rashes, swelling, itching and cracking. If you have one of these symptoms, researchers suggest looking for a chemical named linalool in the ingredients' list on shampoos, conditioners and other liquid hygiene products.
When exposed to air, linalool becomes an allergen. Experts suggest that if you use a product that includes linalool, make sure to replace the cap after each use, and don't buy it in bulk.