By Dana Crosby, MD, FAAOA WHY DO I NEED TO STOP SOME MEDICATIONS BEFORE AN ALLERGY TEST? When you are allergic to a substance, your body releases certain chemicals such as histamine. When these chemicals are released in the skin…
By Christine DeMason, MD
While patients with a cold and allergies generally have the same symptoms (runny nose, nasal drainage, congestion and cough), they are different diseases.
A cold is caused by a virus that affects the upper respiratory tract (primarily the nose). This leads to symptoms such as runny nose, nasal congestion, cough, sore throat, and sneezing. Patients with a cold are more likely to have general aches/pain and low-grade fever than patients with allergies. Nasal drainage is usually thick and yellow/green.
There are many different viruses that cause a common cold with the most common being rhinovirus. Symptoms usually last for 1-2 weeks. A cold is acquired when coming into contact with the virus from another person – either by direct physical contact from a contaminated surface or from respiratory droplets from a sneeze or cough. Treatment includes pain relievers such as Tylenol, nasal decongestants, expectorants (loosens mucus) and cough suppressants.
On the other hand, allergies are caused by an abnormal immune response in the body to an environmental substance. The substance can be inhaled, ingested or come into contact with the skin. The body is too hypersensitive to these substances which include such substances as pollen, dust, medications, bee sting and peanuts.
The immune system treats these substances as if they are harmful to the body (as it does with a virus) and attacks it. The body releases histamine which leads to inflammation and swelling. This is why the symptoms of allergies and a cold are similar. These include sneezing, runny nose, nasal congestion and drainage. Watery, itchy eyes is more common in allergies than with a cold. Patients with allergies can have a cough and sore throat but these are more severe with a cold. Nasal drainage is usually clear and thin. Depending on the environmental substance, these symptoms can last for weeks, months or even all year round.
This is all mediated by a specific antibody in the body called IgE. Allergy treatment focuses on reducing this hypersensitizes by blocking certain parts of this process such as antihistamines block histamine and allergy shots decrease IgE levels.
|Duration||1-2 weeks||Varies- Weeks, months, years|
|Nasal drainage||Thick yellow/green mucus||Thin clear mucus|