Immunology is the branch of medicine that deals with the structures and functions of the immune system, focusing on the development, anatomy, and problems that can arise from it.

What does an immunologist do?

An immunologist takes care of the immune system of a patient and works closely with universities or other research institutions to determine the mechanisms of operation, and study the causes and treatments of diseases that can effect the immune system.

What are the diseases treated by an immunologist?

Among the diseases an immunologist can treat are allergies and hypersensitivity reactions such as anaphylaxis, immunodeficiencies associated with diseases such as diabetes, chronic granulomatous disease or HIV infection, autoimmune diseases such as lupus erythematosus, rheumatoid arthritis, hashimoto's thyroiditis and myasthenia gravis, and other diseases or disorders involving the immune system. 
An immunologist also deals with vaccines and other agents that modify the immune's response against specific pathogens, drugs, and other molecules that balance the activity of the immune system, such as those used to prevent rejection in transplants. 

What are the procedures used by an immunologist?

An immunologist will inquire about the patient medical history such as smoking habits, physical activity and inactivity levels, previous illnesses or surgeries, and a family history of similar diseases.
The doctor will feel the abdominal area, listen to the heart, and measure the blood pressure of the patient and may prescribe further tests to be done if a diagnosis is not reached such as cardiological and radiological examinations, blood tests, genetic testing, and a test for the search of autoantibodies. 

When should a patient visit an immunologist?

A patient can visit an immunologist if they suspect an allergy or inflammation of unknown origin associated with fever and weight loss. Other reasons include to follow up on immunotherapy, or if the patient is having issues in managing asthma problems, or is dealing with anaphylaxis.