-HIV/AIDS- an acquired viral infection that destroys important white blood cells and weakens the immune system.
-Severe combined immunodeficiency (SCID). This is an example of an immune deficiency that is present at birth. Children are in constant danger of infections from bacteria, viruses, and fungi.
-Temporary acquired immune deficiencies. Your immune system can be weakened by certain medicines, for example. This can happen to people on chemotherapy or other drugs used to treat cancer.
-Asthma. The response in your lungs can cause coughing, wheezing, and trouble breathing. Asthma can be triggered by common allergens like dust or pollen or by an irritant like tobacco smoke.
-Eczema. An allergen causes an itchy rash known as atopic dermatitis.
-Allergic rhinitis. Sneezing, a runny nose, sniffling, and swelling of your nasal passages from indoor allergens like dust and pets or outdoor allergens like pollens or molds.