An allergic reaction occurs when your immune system overreacts to a typically harmless substance, such as pollen, pet dander, or certain foods.
Allergies are relatively common, affecting up to 30% of people. While allergies typically develop early in life, it is possible to develop later.
Allergic Sensitization and Response
The first step in the allergy development process is called sensitization. This occurs when you’re exposed to an allergen and, for some reason, your immune system begins producing antibodies to that particular allergen.
The next time you’re exposed to that same allergen, those antibodies signal your immune system to release histamine and other chemicals into your bloodstream. Your immune system tries to protect you by:
- dilating your blood vessels
- forming mucus
- stimulating sneezing and coughing
- triggering bowel movements
- skin irritation and itchiness
- swelling tissues
- closing your airways
This immune response would help block the spread and remove the toxin if you were truly exposed to a dangerous substance. But since harmless substances usually trigger allergies, this response is often more problematic than the allergen itself.
Allergies usually develop in the first contact with an allergen in childhood, but in some cases, an allergic reaction may first appear later in life.
This could be because you moved or traveled to a new area and are now exposed to new types of pollen or other environmental allergens.
It may also happen if you are exposed to a potential allergen when your immune system is weakened due to illness, stress, pregnancy, or certain medications. So even if you weren’t allergic to that thing before, your confused immune system may now consider it dangerous and overreact.
Older adults may also develop new allergies as immunosenescence (the gradual change and deterioration of the immune system with age) develops.
Beware of Warning Signs
While some allergies are mild and cause a runny nose or itchy eyes, others can be life-threatening.
Call for help or dial 911 if you or someone around you experiences symptoms including:
- difficulty breathing
- swelling of the tongue or throat
- large rashes or hives
- abdominal cramps
- confusion or dizziness
- fainting or loss of consciousness
Allergy Treatment and Management
For mild allergic reactions, over-the-counter antihistamines may be enough to provide relief from symptoms.
If your allergies are more severe, you may need a prescription-strength antihistamine or other medication, such as an epinephrine injector (EpiPen), to carry with you in case of an emergency.
For a long-term solution, you may have the option to receive immunotherapy treatment, which involves controlled exposure to the allergen to train your immune system not to overreact, similar to a vaccine.
Talk to your doctors about getting tested for allergies and finding the best treatment option for you.