Symptoms
Respiratory Allergies
- Sneezing
- Runny nose
- Nasal congestion
- Itching of nose, upper mouth, eyes, and ears
- Irritation and swelling of the eyes
- Bloodshot eyes
- Headache
- Loss of concentration
- Rare cases:
- Loss of smell/taste
Food Allergies
- Inflamed and itchy skin
- Weight loss
- Swelling
- Diarrhea
- Vomiting
- Blood in stool
- Rare cases:
- Anaphylactic shock
Description
An allergy occurs when the body's immune system overreacts to an ordinary substance
that would cause no reaction in most people. Some individuals are overly sensitive
to certain substances (e.g. pollen, dust, and some foods) and the immune system
responds to exposure to these materials by defending itself as if they were a threat.
The substances that produce an allergic reaction are called allergens. Allergens
can enter the body by inhalation through the nose and mouth as well as orally by
the ingestion of food. An allergic response to an airborne allergen is called allergic
rhinitis, while an allergic response to certain foods is referred to as a food allergy.
Allergies are more common in children, though a person can develop an allergy at
any age. Some allergies can go away and return later in life.
Causes
Allergies are believed to be an inherited characteristic though not everyone will
develop an allergy, even if they received the genes from their parents. Development
may depend on exposure to the allergen, and people may also be more susceptible
to developing an allergy when their bodies are weak, after illness, or pregnancy.
Respiratory allergies can be due to air borne seasonal allergens (pollen and mold),
or permanent airborne allergens (dust, pets, and cockroaches). Many types of food
can cause food allergy. The most common are peanuts, tree nuts, shellfish, fish,
milk, and eggs.
Treatment
The best treatment approach for allergies depends on the duration of symptoms, severity
of the allergies, and the patient’s response to different treatment options. The
most basic approach is to avoid the substances that cause allergic reactions. In
the case of nasal allergies, many of these substances occur naturally in homes and
outdoors, making medication the most common and effective option.
There are four main types of medication used to treat allergic rhinitis:
- Nasal decongestant -
Pseudoephedrine (Afrinol*, Sudafed*) reduces congestion temporarily by making the
blood vessels of the nose smaller.
- Antihistamines -
Cetirizine (Zyrtec*) and loratadine (Claritin*, Alavert*) help with itchiness, runny
nose, sneezing, and eye problems.
- Steroid nasal sprays -
Fluticasone spray (Flonase*) and flunisolide spray relieve sinus inflammation and
congestion.
- Leukotriene receptor antagonists -
Montelukast (Singulair*) and zafirlukast (Accolate*) used to prevent the narrowing
of the air passageways in the lungs.
In the case of food allergies, medications (like antihistamines and steroids) may
help with symptoms, but a typical treatment strategy is to eliminate the problem
foods from the patient’s diet. A potentially fatal reaction to an allergy-causing
food, called anaphylactic shock, may be treated with adrenaline injections.