How to Tell If You Have Allergies or Something Else

The common cold is a mild upper respiratory infection that generally goes away on its own after a few days. It can be unpleasant and inconvenient, but it usually won’t cause you to stay in bed all day and doesn’t require medical care.

While many different respiratory viruses can cause the common cold, hallmark symptoms include:

• nasal stuffiness and/or runny nose
• sneezing
• sore throat
• cough

Depending on the virus causing your cold, you may also experience:

• sinus pressure
• headache
• fatigue
• body aches
• low grade fever (rare)

Even though your body’s immune response is different for a cold compared to an allergy, the outward symptoms can be very similar. Colds and allergies both regularly feature:

• runny or stuffy nose
• sneezing
• sinus congestion
• post nasal drip (mucous leaking down the back of the throat)

Coughing, sore throat, and general fatigue are more common with a cold but can sometimes occur with allergies as well.

Unlike a cold, an allergy won’t cause a true fever. Fevers are a protective response that stimulate your immune cells and elevate your body temperature to limit the growth and spread of a virus or bacteria.

Allergies are more likely than colds to involve:

• wheezing
• watery and/or itchy eyes
• hives and rashes
• itchy nose
• facial swelling
• stomach upset

Your allergy symptoms will depend on your allergy exposure. Airborne allergens, for example, may be more likely to cause respiratory symptoms than contact allergies, which usually cause a localized reaction on your skin.

Similarly, if you eat something you’re allergic to, you may be more likely to experience gastrointestinal symptoms.

Here is a breakdown of some common symptoms of allergies and colds:

Differences in symptom characteristics

Symptoms aren’t the only way to distinguish allergies from a cold. How long they take to appear and how long they last are also good clues.

According to the American Academy of Allergy Asthma & Immunology (AAAAI):

• Colds develop over several days, compared to allergies, which begin shortly after exposure to an allergen.
• Allergies last as long as exposure to an allergen persists, while colds tend to resolve within 3 days.

Seasonal differences

While you can come down with a cold any time of the year, peak cold and flu season occurs during the colder months, particularly between December and February.

Allergies can also be seasonal, and if you live with seasonal allergies, you probably know when to expect them. Spring and summer allergies, for example, might be related to pollen from budding plants. Fall allergies could correspond to late-blooming flowers like ragweed.

Some people have allergies year-round whenever they’re exposed to pet dander, dust, or other irritants.

A stuffy nose and sneezing are vague symptoms. They can represent a mild illness, like a cold or allergy, or they can be the start of something more.

Signs your symptoms may be serious include:

• symptoms persist longer than several days or are progressively worsening
• your nasal discharge contains blood or is thick, yellow, or green in color
• the lymph nodes in your neck are swollen or tender
• a sore throat is severe enough to make you not want to eat or drink
• you feel too sick to do basic daily tasks

With allergies, you can experience a severe and potentially life-threatening reaction is possible anaphylaxis. This medical emergency may start with typical allergy symptoms but then rapidly progresses into a body-wide reaction.

Signs you might be experiencing anaphylaxis include:

• facial swelling
• extreme itching
• skin flushing
• hives
• shortness of breath
• coughing
• chest tightness
• hoarse voice
• rapid heart beat
• low blood pressure
• blue skin tone
• nausea
• vomiting
• dizziness
• confusion
• loss of consciousness
• airway swelling

If you think you or someone you’re with may be experiencing anaphylaxis, seek immediate medical attention.

Many conditions beyond the common cold can cause similar symptoms to allergies, including:

• sinusitis (sinus infection)
• non-allergic rhinitis (nasal inflammation from irritants or infection)
• nasal polyps
• obstruction in the nose
• deviated septum
• asthma
• chronic obstructive pulmonary disease (COPD)
• nasal and sinus cancers

Although they involve allergy-like experiences, these conditions feature their own unique symptoms that help differentiate them from an allergic reaction. If your symptoms don’t respond to antihistamines, they’re likely not caused by allergies.

Your primary care doctor or an allergist can diagnose allergies by reviewing your medical history, the circumstances around your symptoms, and the results of allergy screening tests.

Skin reaction tests, blood tests to measure antibodies and histamine, and nasal smears are several common diagnostic tools used to help diagnose an allergy.

If you visit your doctor within a day or two of not feeling well and don’t have signs of an allergic reaction, a physical examination can provide insight into what’s causing your symptoms.

It’s never too soon to contact your doctor about a runny nose or sneezing. Catching medical conditions early is one of the best ways to find relief and improve your outcome, even with mild illnesses.

Consider speaking with your doctor about allergy-like symptoms if:

• this is the first time you’ve had these symptoms
• symptoms are progressively getting worse
• you develop pain or discomfort in other areas of the body
• you’re feeling too sick to do basic tasks
• symptoms appeared after an injury or exposure to an irritant
• you’re considered high-risk for nasal or sinus cancers
• over-the-counter allergy medications don’t improve symptoms
• your symptoms have been present for more than several days without improvement

Allergies share common symptoms with many other conditions, including the common cold and sinusitis.

While you can often learn to distinguish allergies from other conditions by differences in symptoms, time of onset, and duration, your doctor can help definitively determine if what you’re experiencing is allergies or something else.