Allergy and immunology
In medicine and biology, allergy and immunology is concerned with the health-related interactions of the immune system with living organisms. Medical Subject Headings defines it as "hypersensitivity of the individual to foreign substances and protection from the resultant infection or disorder". 
From a medicial standpoint, it may be a subspecialty of internal medicine or pediatrics. A practitioner of the field is called an allergist, or a clinical immunologist if more concerned with specialized mechanisms.
It also includes the biological scientific study of immunology and the development of laboratory support for immune phenomena, and can include the clinical and research aspects of cytokines triggered by immune phenomena, as well as the genetics of immune reactions.
In the United States, there are three organizations involved in graduate medical education and clinical practice:
- American Academy of Allergy, Asthma & Immunology
- American Association of Immunologists
- American Board of Allergy and Immunology, responsible for training and board certification Preparation for certification usually involves a two-year fellowship after a residency in internal medicine or pediatrics
Medically, the field has many interdisciplinary aspects. Asthma treatment may be by a pulmonologist with consultation from allergists, but allergists, especially in pediatrics, may be the principal care providers. The care of allergic rhinitis, in like manner, may be led by an allergist or otorhinolaryngologist.