The exact cause of eczema is unknown, but it is thought to be a natural body reaction to an allergen or irritant. Sometimes stress, weather changes or illness can trigger eczema. Exposure to certain chemicals that cause irritation such as household cleaning products or acetone can cause an outbreak. Certain people are sensitive to pet dander and pollen, causing a flare.
Eczema is not contagious and can't be spread from person to person.