Hello again, dear readers! Welcome to a bonus letters column. This time, we're focusing on two questions, one important and one just plain interesting, so let's dive in.
A reader from San Diego is worried about the upcoming cold and flu season. He echoes the concerns of many people making a post-pandemic return to the office. “During the two years we were working from home, I never got sick once,” he wrote. “We were back for just a month when a co-worker came in with the flu and spread it to a bunch of us. Can you please talk about why you should stay home when you're sick?”
Just a moment of contact with the flu virus can lead to a full-blown infection. The droplets released in a cough or sneeze from an infected person can hang in the air for a surprisingly long time. Large droplets may last a minute or two, while smaller ones -- still carrying the virus -- can stay suspended for hours. You can either breathe these in, or they may settle on commonly touched surfaces such as desks, keyboards, doorknobs or coffeepots. This is especially true in poorly ventilated indoor spaces.
A case of the flu strains the heart and lungs, worsens asthma and, for older adults or immunocompromised people, can escalate to pneumonia. Even healthy young adults can develop inflammation and lingering fatigue. All of this makes the first rule of flu etiquette simple: Stay home. When you do return to your routine, take steps to prevent spreading any lingering virus particles -- wear a mask, wash your hands often, dispose of used tissues carefully and hold off on hugs or kisses.
We also heard from a reader in New Hampshire asking about the phenomenon known as brain freeze. “My 5-year-old son took a big bite of his Popsicle, grabbed his head and burst out crying,” she wrote. “His first brain freeze. If the cold food is in your mouth, why does it make your forehead ache?”
Brain freeze, also known as an ice cream headache, is a fascinating phenomenon. Swift and surprisingly painful, it's triggered when something very cold rapidly chills the roof of your mouth. Ice cream is the classic culprit, but Popsicles, slushies, smoothies, frozen fruit or even a gulp of cold soda can bring the pain.
The reason lies in simple physics. The sudden chill causes blood vessels in the palate to constrict and then quickly dilate. This effect activates pain receptors that communicate through the trigeminal nerve, the conduit for facial pain. When the “ouch!” message reaches the brain, it’s misread as coming from the forehead or behind the eyes. Even though the source is in the palate, the brain tells a story about forehead pain. Happily, brain freeze is short-lived. You can speed relief by warming the roof of your mouth with your tongue, or just approach that chilly treat with a bit more caution.
Thank you to everyone who took the time to write. We love hearing from you. We will be back soon with more of your thoughts and questions in our regular monthly letters column.
(Send your questions to [email protected], or write: Ask the Doctors, c/o UCLA Health Sciences Media Relations, 10960 Wilshire Blvd., Suite 1955, Los Angeles, CA, 90024. Owing to the volume of mail, personal replies cannot be provided.)
