Here’s one thing you can count on: The flu season is unpredictable. Some years it might be mild, and others it could be brutal.

Why is one flu season worse than another? Two reasons. First, the flu vaccine may not cover the dominant strain of flu that’s circulating in a given year. And second, the strain could be a particularly severe one, more likely to cause complications that may become fatal. Influenza A, or H3N2, is particularly likely to send people to the hospital.

Flu symptoms cheat sheet

People often confuse the flu with symptoms of gastroenteritis – vomiting and diarrhea. Flu symptoms include:

  • Fever that abruptly comes on and rises
  • Headache
  • Body aches
  • Cough
  • Sore throat
  • Runny nose
  • An overall feeling of absolute crumminess (yes, that’s a medical term)
  • Lack of energy

Steps to take if flu symptoms start

  • Antiviral medications only have a chance of working if started in the first 24 to 48 hours. So call your doctor about a rapid-flu test [Insert click-to-call hyperlink OR link to online appointment scheduling OR link to Ask a Nurse] and discuss whether you would benefit from antiviral medications at all. Antiviral meds only shorten the symptoms by about one to two days; your doctor may feel that the risk of side effects outweigh the benefits.
  • It’s especially important to ask about antivirals for: young children, adults over 65, pregnant women (or up to two weeks postpartum) and anyone who has chronic conditions (including, but not limited to, immune system compromise, asthma, COPD, diabetes and heart disease).
  • If all else fails and you have the flu, you'll need to rest. Expect to be sick for about two to five days. Try to avoid contact with others since you’ll be contagious for four to five days. Hydrate, take acetaminophen or ibuprofen for body aches and fever; take cough and nasal congestion remedies as needed.

When to seek medical care

Most children and adults will get better on their own without specific medications or care. However, a small percentage will develop severe complications. Here’s what to look for:

  • Difficulty breathing (In adults, this shows as rapid or shallow breathing, wheezing or being unable to catch their breath. In children, additional signs include obvious straining of their chest and neck muscles, blue around their lips, wheezing or barking cough or leaning forward to breathe.)
  • A high fever that doesn’t improve with acetaminophen or ibuprofen
  • Lethargy or other alteration in behavior (Lethargy is worse than general “crumminess” – it means you have trouble awakening the person, even to eat or drink, and they just seem really out of it). Other signs can include confusion or difficulty walking.
  • Refusing to eat or drink anything (especially if showing signs of dehydration such as decreased urination, a very dry mouth and eyes)
  • Significant vomiting. While vomiting isn’t a typical flu symptom, it can occur in younger children. If your child can’t keep down food or fluids, call your doctor.
  • Productive cough. That is, a cough that goes from dry to production of phlegm
  • Severe ear pain (ear infection can be a complication, especially in kids)

If you or a loved one is experiencing any of the above complications, visit your nearest emergency room right away.

This content originally appeared on Sharecare.com.