Not to be confused with hemostasis. Homeostasis or homoeostasis (homeo- + -stasis) is the property of a system in which variables are regulated so that internal conditions remain stable and relatively constant. Examples of homeostasis include the regulation of temperature and the balance between acidity and alkalinity (pH). It is a process that maintains the stability of the human body's internal environment in response to changes in external conditions.
Allergies, also known as allergic diseases, are a number of conditions caused by hypersensitivity of the immune system to something in the environment that usually causes little problem in most people.
Histamine is a chemical our bodies produce naturally, and it's also found in certain foods. In situations involving true allergies, your body releases histamine, and that histamine, in turn, provokes the response we think of as an allergic reaction. Histamine intolerance isn't a true allergic reaction.