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.
Allergy Facts and Figures. An allergy is when your immune system reacts to a foreign substance, called an allergen. It could be something you eat, inhale into your lungs, inject into your body or touch. This reaction could cause coughing, sneezing, itchy eyes, a runny nose and a scratchy throat.