Why are steroids not given for extreme allergy?

Sometimes they are: They are sometimes. It depends on the symptoms, the severity of the symptoms, length of time you've been afflicted. It's situational, though, so I wonder if your doctor has good reason not to prescribe them for you. If you've tried everything else, see an allergist, get tested, and consider allergy shots for more long-term relief.

Allergies: Steroids are usually given to treat an allergic reaction and sometimes high dose steroids are required for a severe allergic reaction. However, there are times when one tries to avoid steroids if possible in such conditions such as poorly controlled hypertension or Diabetes, an underlying infection or other contraindication to steroids.