Immunology
Explanation:
Hives are red swollen bumps on the skin and are often associated with allergies. Again respiratory distress is among the severe responses of Allergy.
Since, the cause and pattern of these symptoms are already known. The diagnostic procedure cannot be referred to epidemiology.
Apparently the symptoms are due to the immune response of the persons body. The for diagnosis and treatment of this person will be concerned under the immunology.
Because, Immunology is the branch of microbiology that deals with the study of immune system , molecules involved i immune responses and their causes.