Mast cells are a type of white blood cell that play a crucial role in the immune system. They are primarily found in tissues throughout the body, especially in the skin, lungs, and digestive system. These cells are involved in allergic reactions and help protect the body from pathogens by releasing chemicals like histamine. When activated, mast cells release these chemicals, which can cause inflammation and other symptoms associated with allergies, such as itching and swelling. They also contribute to wound healing and defense against infections. Understanding mast cells is important for managing conditions like asthma and anaphylaxis.