Because allergic reactions can progress and worsen in minutes, medical attention is always recommended for all but the most minor and localized symptoms.

If the symptoms of your reaction get worse over a few days, or if they do not get better with recommended treatment and removal of the allergen, you should call your health-care provider.

Tell your health-care provider if you have any allergic symptoms after using a drug or other treatment he or she prescribed for you (see Drug Allergy).

Allergic reactions can be dangerous. Sudden, severe, widespread reactions require emergency evaluation by a medical professional. Call an ambulance if you or someone around you has any of the following with an allergic reaction:

• sudden, severe, or rapidly worsening symptoms

• exposure to an allergen that previously caused severe or bad reactions

• swelling of the lips, tongue, or throat

• wheezing, chest tightness, loud breathing, or trouble breathing

• confusion, sweating, nausea, or vomiting

• widespread rash

• collapse or unconsciousness