Got a Cold or Flu, Plus Diabetes?

Medically Reviewed by Michael Dansinger, MD on May 21, 2023
5 min read

Colds and flu are no fun, and they can be even worse if you have type 1 or type 2 diabetes. Infections, dehydration, and sugar in some medicines can make it harder to manage your blood sugar.

You can take steps to help prevent those problems and stay well.

When you have a cold, your body sends out hormones to fight the infection. The downside: That makes it hard for you to use insulin properly, and your blood sugar levels may rise.

If you have type 1 diabetes and your blood sugar levels get hard to manage, it can lead to problems like ketoacidosis. That's a buildup of too much acid in your blood, and it can be life-threatening.

If you have type 2 diabetes, especially if you're older, very high blood sugar can bring on a serious condition called diabetic coma.

Make sure you and your family members wash your hands regularly. There's no vaccine against colds, but your best move is to get a flu shot every year. The CDC recommends that for everyone age 6 months and older, so if you have a child with diabetes, make sure that they get vaccinated, too.

A flu vaccine can prevent many types of flu or keep flu viruses from making you so ill. September may be the best month to get this vaccine because it protects you for about 6 months. But you can get a flu shot at any time during flu season.

Ask family members, co-workers, and close friends to get the vaccine, too. You're less likely to get the flu if those around you don't have it.

Ask your doctor if you need the pneumonia shot. This vaccine can also help protect you from blood infections and meningitis.

According to the American Diabetes Association, only 1 out of every 3 people with diabetes ever gets this shot. Yet people with diabetes are about three times more likely to die from flu and pneumonia.

The main problem for people with diabetes is that some cold and flu drugs, such as cough syrups or liquid medicines, have sugar in them. Read the ingredients label carefully. Ask your doctor or pharmacist to recommend over-the-counter drugs that are safe for you. Keep those product names handy for future reference.

If you have high blood pressure, avoid any cold medicine that contains decongestants, which can raise it even more.

Don’t give cold and flu medicines to a child younger than 2, whether they have diabetes or not, because of the risk of serious side effects.

Everyone gets a cold or flu sometime. Your doctor, nurse, or diabetes educator can help you prepare. They'll probably recommend that you do the following in addition to regular things like staying home from work, school, or day care if you’re too sick to go.

Check your blood sugar levels every 4 hours, or as often as recommended by your doctor. If your levels aren't near your target, you can tweak your diabetes management plan. Your doctor may tell you to use more insulin if your blood sugar levels are too high.

Test for ketones if your blood sugar level is over 240 milligrams per deciliter (mg/dL). Call your doctor if it shows any ketones.

Take your temperature regularly.

You may not feel hungry when you first get sick, but it's important to try to eat something anyway. If you don't eat, your blood sugar might fall too low.

You can have foods from your regular meal plan. If you have a fever, vomiting, or diarrhea, drink 1 cup of liquid every hour you're awake. Water and broth are good choices. You can sip the liquid if you want -- no need to gulp it down all at once. The important thing is to avoid getting dehydrated.

If your blood sugar is too high, sip liquids like water, tea, or sugar-free ginger ale. If it's too low, try something that has about 15 grams of carbs. Sip half a cup of apple juice, a quarter-cup of grape juice, 1 cup of a sports drink, or a half-cup of ginger ale. Always check what you eat or drink against your regular diabetes diet to make sure these foods and drinks are allowed in your situation.

Try to eat 35-50 grams of carbohydrates every 3 to 4 hours. If you can't eat solid food, try clear soup, regular soft drinks, Popsicles, unsweetened applesauce, apple juice, or sports drinks.

Keep taking insulin or other diabetes medications unless your doctor tells you not to.

If you or your child has diabetes as well as what you think might be the flu, call your doctor right away so you can start treatment to help prevent serious complications.

For adults, call your doctor if your symptoms are really bad, have lasted for a few days, or if you’ve had a fever that won’t let up. You should also call if:

  • It’s hard to breathe.
  • Your blood sugar level remains higher than 180 milligrams per deciliter (mg/dL).
  • Your blood sugar level remains lower than 70 mg/dL.
  • You cannot keep down solids or liquids.
  • Your temperature is over 101 F.
  • You have vomiting or diarrhea.

For children, call the doctor if they have:

  • Trouble breathing
  • Blue lips
  • Won’t eat or drink
  • Ear pain
  • A fever of 102 F or higher (or any temperature if it’s a baby age 2 months or younger)
  • A lot more crankiness or sleepiness than usual
  • Worsening symptoms