These two compounds can cause liver and kidney damage, yet for years these products were incorporated into baby foods. Many countries have banned their use and importation. There are other chemicals such as ethoxiquin, a known carcinogen, sodium nitrate and nitrite, red dye 40, propylene glycol. The list goes on and on. All of these and more can cause skin allergies in your pets.
Hormone imbalances are also causes of skin allergies.
L-thyroxine, one of the thyroid hormones, is extremely essential for skin integrity. When this hormone is in short supply, the animal scratches constantly which causes chronic inflammation. This is most often observed in altered animals. They have multiple functions. When an animal is de-sexed, the immune system is compromised, i.e., the animal's resistance is weakened.