Even if you think you can go to work when you have a cold or flu, you need to think about others, an infectious disease expert says.
"I see a lot of patients whose jobs and stress make them feel torn between staying home and going in when they're sick," said Dr Robin Wigmore. She is a primary care physician and infectious disease specialist at Beth Israel Deaconess Medical Center in Boston.
"But viral infections like the common cold and flu are contagious. It's important to consider your co-workers' health as well," Wigmore said in a medical center news release.
To make an informed decision, first consider how long you've been feeling ill.
"You are most contagious in the first 48 hours of a viral illness," Wigmore explained. "This is often even before you begin feeling symptoms."
This means you should stay home at the first sign of symptoms. That will avoid spreading your illness and allow you to rest, stay hydrated and take care of yourself.
Ask yourself if your symptoms are contagious. Viruses can be passed through the air by coughing or sneezing, and some cold and flu germs can survive on surfaces such as countertops, doorknobs and phones for up to 24 hours.
"As a general rule, if you have a wet cough, a runny nose, fevers or aches, you should probably stay at home," Wigmore advised.
Stay away until fever-free
If you have a runny nose without aches or fever, you may be suffering from allergies. A dry, "clear your throat" type of cough or tickle may also be allergies or irritation. In that case, it's likely OK to go to work, she said.
"But if your runny nose is accompanied with thick, yellow or green mucus, this is an indication that your body is fighting off an illness," Wigmore noted. "In this case, you should stay home."
Stay home and call your doctor if your throat hurts and you have aches, including headache, and/or you see white patches on your tonsils. This could be strep throat.
If your temperature is higher than 100.4 degrees Fahrenheit (38°C), that's a strong sign of infection - and maybe the flu. In that case, "you should call your doctor and stay home", Wigmore said. "It is often best - and many times, company policy - that employees stay out of work until they are fever-free for 24 hours, especially with the flu."
Nasal congestion with sinus or facial pain indicates a sinus infection. Sinus infections can be viral or bacterial. Viral sinus infections are often contagious.
"Either way, it's best to stay home," Wigmore added.