Differences between Allergy and Common Cold
Contents
Allergy vs. Common Cold
Allergies and the common cold can present with similar symptoms, such as a runny nose, sneezing, and coughing, which can make it difficult to distinguish between the two.[1][2] However, they are distinct conditions with different causes and treatments. A primary difference is that the common cold is caused by a virus, making it contagious, while allergies are an immune system response to allergens and are not contagious.[2]
Comparison Table
| Category | Allergy | Common Cold |
|---|---|---|
| Cause | Immune system reaction to an allergen (e.g., pollen, dust mites, pet dander)[3] | Viral infection of the upper respiratory tract[4] |
| Symptom Onset | Immediately after exposure to an allergen[1] | A few days after viral infection[1] |
| Duration | Can last for days, weeks, or months, as long as there is exposure to the allergen[1] | Typically 3 to 14 days[1] |
| Itchy, Watery Eyes | Common[1] | Rare[1] |
| Fever | Never[1] | Sometimes, usually low-grade[5] |
| Body Aches | Never[1] | Sometimes[5] |
| Sore Throat | Rarely | Often[1] |
Causes
The common cold is a viral infectious disease of the upper respiratory tract. Over 200 different viruses can cause a cold, with rhinoviruses being the most common culprits.[5][4] These viruses are typically spread through airborne droplets from coughs and sneezes, or by touching contaminated surfaces and then touching the mouth, nose, or eyes.[4]
Allergies are the result of the body's immune system overreacting to a normally harmless substance known as an allergen. When a person with allergies comes into contact with an allergen, their immune system releases chemicals, such as histamine, which cause allergy symptoms. Common allergens include pollen, dust mites, mold spores, pet dander, certain foods, and insect stings.
Symptoms and Diagnosis
While both conditions share symptoms like a runny or stuffy nose and sneezing, some signs are more indicative of one over the other.[1] Itchy eyes are a very common symptom of allergies but are rare with a cold.[1] A sore throat and body aches are more likely to accompany a cold.[1] Fevers are sometimes present with a cold but never with allergies.[1] The nasal discharge in allergies is typically clear and watery, while it may be thicker and colored in the later stages of a cold.
A healthcare provider can often diagnose a common cold based on a physical examination and a review of symptoms. To diagnose allergies, a doctor may recommend a skin prick test or a blood test. In a skin prick test, a small amount of a potential allergen is placed on the skin, and a reaction indicates an allergy. A blood test can measure the level of specific allergy-related antibodies (IgE) in the blood.
Treatment
There is no cure for the common cold; treatment focuses on relieving symptoms and includes getting adequate rest and staying hydrated. Over-the-counter medications can also be used to manage symptoms. Since colds are caused by viruses, antibiotics are not an effective treatment.
For allergies, treatment often involves avoiding the allergen if possible. Over-the-counter or prescription medications like antihistamines, nasal corticosteroid sprays, and decongestants can help manage symptoms. Antihistamines work by blocking the effects of histamine, which is released during an allergic reaction.
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 "mayoclinichealthsystem.org". Retrieved February 04, 2026.
- ↑ 2.0 2.1 "pfizer.com". Retrieved February 04, 2026.
- ↑ "bouldermedicalcenter.com". Retrieved February 04, 2026.
- ↑ 4.0 4.1 4.2 "mayoclinic.org". Retrieved February 04, 2026.
- ↑ 5.0 5.1 5.2 "mayoclinic.org". Retrieved February 04, 2026.
