Can there be an illness referred to as over active immune system?

Allergy & autoimmune: While the immune system is typically held in check, times when it becomes overactive include: allergies--the bodies immune system reacts to substances (proteins) that other people don't react to such as pollens, foods, drugs, etc. Also, in autoimmune diseases, the body reacts to "itself" or self-antigens (example is lupus).