What is an allergy?

Abnormal reaction. An allergy is an abnormal, incorrect reaction of the immune system against substances we are exposed to in our environment. This includes environmental exposures, foods, drugs, etc. Allergies must be differentiated from other reactions not mediated specifically through the immune system including irritants, intolerance, etc. In general, allergy involves the respiratory tract, skin, or GI system.
Immune Over-reaction. Allergy is like the dog biting the mailman. Dogs are supposed to welcome friends & attack foes. When the immune system (dog) mistakes a harmless substance (like food) for a dangerous one (like an infection) the over-reaction results in symptoms we call allergy. When the immune system needlessly attacks parts of our own body the result is autoimmune disease. Harder question - why does this happen?
Misdirected response. An allergy is an abnormal response by a component of the immune system to certain foreign proteins encountered by the body. These proteins are generally not harmful (e.g. Foods, pollen) but for reasons which are yet unclear, trigger a response by this component of the immune system which under "normal" circumstances should only target parasites. This immune reaction then causes allergy symptoms.

Related Questions

What are good allergy reliefs?

Several. Over the counter you have allegra, zyrtec and Claritin and saline nasal spray. Prescription medications are numerous and the ltimate in long term relief is allergen desensitization. See an allergist to discus. Your options. Read more...
Allergen avoidance. The best one off course is to avoid the allergen completely if you can. Many times, you can't either because you don't know the allergen or you can't really avoid the allergen. So, in that case, you can try otc medication like anti histamin ( benadryl) or other medication like claritin, (loratadine) zyrtec, allergra etc. Try one- see which one works better for you. Discuss further with your doctor. Read more...

What causes an allergy attack?

Acute allergy. There are actually different types like the delayed ones. The common ones are the acute allergic reaction. You have allergy cells (eosinophils, basophils, mast) with receptors on the surface. The allergen (the cause) binds to those receptors, the cells lyse, recruit other cells, but the contents cause the blood vessels and surrounding tissue to react and cause the wheal and flare reaction. Read more...

What could cause allergies all year long?

All year long. Most commonly dust mites and molds and pets. In rare cases, what you work around. Read more...

What is an allergy compared to intolerance?

Immune system. Allergy is caused by an immune response (usually IgE) to a foreign agent- usually a protein. Intolerance is not mediated by an immune system but something unique to that person. Some may be psychological in nature. Read more...

What can untreated allergies do to your body?

Usually Nothing. Allergies to airborne particles cause multiple symptoms which are frustrating but usually won't cause long-term issues. Occasionally untreated allergies are associated with chronic infections (like sinusitis), asthma, and eczema. Rarely, untreated allergies can cause scarring in the nose and sinuses that may require surgery to relieve. Read more...
Depends on location. Untreated allergic rhinitis (hay fever) can increase your risk of sinus infections and make you miserable but likely will not lead to irreversible damage. Untreated allergic asthma however can lead to chronic inflammation in the lungs and possible irreversible changes with low lung function and symptoms. Even if one ignores nasal allergies, do not ignore asthma. Read more...

What are safe allergy medications for toddlers?

Avoidance. The safest treatment is allergen avoidance. Seek the advice of an Allergist to help identify triggers (both by discussing symptoms and history and skin testing if appropriate). Believe it or not, there of successful strategies for avoidance in many cases. Zyrtec (cetirizine) is often effective treatment. If 2.5mg most days does not effectively treat symptoms, recommend an eval. Read more...
Allergy meds. There are several medications for allergies that can be used for toddlers including: Claritin (Loratadine) Zyrtec (Cetirizine) Allerga (Fexofenadine) Benadryl (Diphenjydramine) Read more...
Many. Most antihistamines are safe when given in the proper dose yet they are often ineffective. For severe cases, nasal steroid , nasal antihistamine, or Singulair (montelukast) may be used even if not yet FDA approved since they have a good risk/benefit ratio. However you will need to check with your doctor prior to using these medications . See an allergist if needed. Read more...

What causes my allergy-like symptoms if it's not allergies?

Many causes. Clarify by describing your symptoms. Non-allergic rhinitis can be just as bothersome and harder to treat. Allergies only trigger a fraction of asthma exacerbations - eczema and hives also. An allergist is trained in evaluating these conditions. . Read more...

What type of allergies can the medication Singular help with?

Leukotrienes. Montelukast (Singulair) is a specific blocker of leukotrienes which are inflammatory molecules formed by eosinophils and mast cells which are cells involved in allergic response. Response to montelukast is variable but may be very helpful in those with asthma. Read more...
Nose and chest. Dr Fisher has given a good description on its action. In addition to asthma, Singulair (montelukast) may also be effective for allergic rhinitis. In my experience, it is effective in about 50% of the people. Singulair (montelukast) is not as effective as inhaled steroid but may be uniquely effective about 25% of the time. Read more...