One in 6 Americans gets food poisoning each year, but how do you know if that’s what you have? Food poisoning and stomach flu (or “gastroenteritis” which is different from influenza) can look similar, and they share some symptoms with food allergies.

Generally speaking, stomach discomfort (cramps or pain), vomiting or diarrhea could be symptoms you experience with any of these three conditions. So it’s important to pay attention to other signs – including how long your symptoms last – that might help you be prepared for a conversation with your doctor if you need to seek medical care.

Here’s how to tell them apart:

Food poisoning

What causes it

Food poisoning happens when you eat or drink something contaminated by bacteria, viruses, parasites, chemicals or metals. One less common cause of food poisoning is listeria, an unusual type of bacteria that grows in cold temperatures.

What other symptoms to look for

Nausea is also a common symptom of food poisoning and after it sets in, you’re likely to experience dehydration which has its own set of symptoms, such as body aches, headache and increased thirst. Confusion and a stiff neck, can also be signs of listeria.

How long it lasts

Most food poisoning takes about 3-6 hours to affect you, but it can take up to 24. Symptoms typically last 6-12 hours, and most people recover within a few days without seeking medical treatment. Food poisoning caused by certain bacteria like Campylobacter or Listeria can take even longer to develop or show symptoms.

Who’s at risk

• Babies, children, seniors, pregnant women and people with compromised immune systems are at higher risk of being affected by food poisoning.
• People with illnesses like kidney disease, heart problems or issues with dehydration should consider seeking treatment in severe cases.
• Anyone eating outdoors in the summer. Food can spoil in less than an hourin 90-degree heat, which isn’t uncommon in Tennessee.

How to treat it

1. Avoid fluids for the first few hours and try to rest.
2. Try taking small sips of water every hour. Once you’re able to keep those down:
3. Consider a rehydration solution or sports drink that contains electrolytes.
4. When you feel well enough to try solid food, start with bland foods like crackers, toast or cereal.
5. Avoid carbonated drinks, caffeine, dairy, alcohol and fatty or sweet foods.
6. Toddlers/infants, women who are pregnant, people 60 and older, or if you have a weak immune system, diabetes or kidney disease, should see a doctor.

You should also seek medical care if you have a fever higher than 101, blood in your stool or vomit, diarrhea lasting longer than 2 days, extreme dehydration, blurred vision, tingling in your arm, or intense abdominal pain or the sensation that your abdomen is sticking out, which could be an appendicitis or hernia.

If you’ve had food poisoning before and recognize the symptoms, you may also want to consider a virtual doctor visit. Your provider may be able to call in nausea medication to help you manage your recovery.

Stomach flu

What causes it

“Stomach bug” and “stomach flu” are terms for viral gastroenteritis, an inflammation of the stomach and intestines caused by a viral infection. Most frequently the stomach flu is caused by norovirus (which is different from the “flu” caused by influenza).

What other symptoms to look for

Like food poisoning, nausea is also a symptom you can experience with the stomach flu. But unlike food poisoning, you can also experience these symptoms right away with the stomach flu:

• Stiff joints
• Weight loss
• Muscle aches
• Thirst
• General feeling of being tired and disinterested in daily activities

How long it lasts

It typically takes 12-48 hours before you feel sick, and symptoms often last 1-3 days. In some cases, you may feel sick for up to 10 days.

Who’s at risk

Everyone. The stomach flu is highly contagious, but in the U.S., most infections occur between October and April. The most common way to get the stomach flu is by being exposed to someone who’s sick, but you can also get it from an infected item (doorknob, refrigerator handle, etc.) or from coming in contact with a sick person’s bodily fluid.

How to treat it

1. Contact your doctor to identify the stomach flu.
2. Once it’s determined that your case is not severe, consider a rehydration solution or sports drink that contains electrolytes.
3. When you feel well enough to try solid food, start with bland foods like crackers, toast or cereal.
4. Avoid carbonated drinks, caffeine, dairy, alcohol and fatty or sweet foods.

Food allergy and intolerance

 What causes it

When you’re allergic to a food, your body reacts the same way it would if you ingested something harmful. Your immune system creates antibodies to fight the “harmful” food, releasing chemicals that can affect your skin, breathing, heart and digestion. Food allergies can cause serious or fatal reactions if not treated immediately.

A food intolerance, on the other hand, is a sensitivity to a food that doesn’t involve the immune system, which means most are unpleasant but not dangerous.

What to look for

Food allergy:

• Trouble breathing
• Coughing, hoarseness or tightness in the throat
• Stomach pain, vomiting or diarrhea
• Itchy, watery or swollen eyes
• Hives, red spots or swelling
• Becoming lightheaded or passing out

Food intolerance:

• Burping
• Indigestion
• Gas
• Incontinence
• Headaches
• Nervousness

How to treat it

Food intolerances can be treated by simply avoiding the food in question. Food allergies, on the other hand, should be treated as emergencies, especially if the reaction is occurring for the first time. If the reaction is not severe, your doctor can take steps to diagnose and help manage further allergic reactions.

Click here to learn more about diagnosing food allergies in our Childhood Food Allergy Guide.

Get more information about specific health terms, topics and conditions to better manage your health on bcbst.com. BlueCross BlueShield of Tennessee members can access wellness-related discounts on fitness products, gym memberships, healthy eating and more through Blue365®. BCBST members can also find tools and resources to help improve health and well-being by logging into BlueAccess and going to the Managing Your Health tab.