A runny nose can be a huge pain. You’re probably constantly reaching for tissues and you have trouble breathing. There are many causes of a runny nose, some more serious than others.

Here are five reasons your nose might be running and what you can do about it:

1. Common Cold

One of the most common reasons for a runny nose is the common cold. It can be caused by viruses or by bacteria that enter the body through the eyes, mouth or nose. In addition to a runny nose, colds are often accompanied by coughing, sneezing, congestions and post-nasal drip. Runny noses caused by viruses are usually clear, while mucus from bacterial colds run green or yellow. Bacterial colds often need antibiotics to fight them. Viruses typically run their course within a week, and there isn’t a medication you can take to correct it. You can treat symptoms with DayClear® Cough, Cold & Flu.

2. Flu

The flu is caused by strains of the influenza virus. It has some similar symptoms to the common cold, such as nasal congestion, runny nose, and a cough, but they’re usually more severe. Coughs from the flu can be dry or with phlegm. The flu also brings chills, fever, dehydration, fatigue, loss of appetite, body aches and even nausea. If you get the flu, you’ll need a lot of rest until you’re better, usually within a week or two.

3. Allergies

A runny nose is one of the most common symptoms of allergies, along with sneezing, scratchy throat and watery eyes. These kinds of reactions are usually triggered by allergens like dust, mold, pollen, cigarette smoke and certain perfumes and fragrances. Many people with allergies have symptoms only at certain times of the year, or in certain buildings or places. Keep your house clean and free of mold and dust, stay away from smoke or anything else that triggers your allergies. If they’re unavoidable, like pollen, take some allergy medication to help you deal with symptoms.

4. Exercise-Induced Rhinitis

Some people experience runny noses when they work out. It’s a fairly common phenomenon called exercise-induced rhinitis (EIR). For sufferers, it causes similar symptoms to allergies, by only while exercising. It’s more common for outdoor exercises in the winter. Some people have exercise-induced asthma, but it’s not clear what causes exercise-induced rhinitis. Some scientists believed that pollution might play a role. EIR doesn’t have any serious consequences; it’s just a nuisance. You certainly don’t want your nose running while you’re jogging or riding your bike. If it really bothers you, use a nasal spray before your workout.

5. Deviated Septum

A deviated septum is when the nasal septum—the bone and cartilage between the nostrils—is crooked or displaced. Sometimes there are no symptoms, but sometimes sufferers experience constant runny noses, congestion, nosebleeds and snoring. People can go for years without realizing they have a deviated septum, blaming symptoms on things like allergies. Most people can live just fine with a deviated septum. Many won’t even realize they have it. Decongestants, allergy medications and adhesive strips to open nasal passageways can help alleviate symptoms. For those with a severe case, surgery may be required.