What Happens When a Mosquito Bite Gets Infected (And What to Do)

“Stop scratching!” That’s good advice, of course. But sometimes it’s easier said than done.

Seemingly blissful summer evenings happen. Sitting outside, without a care. No mosquito spray, citronella candles, long sleeves or pants — big oops! So what do you do the next day (or even day after) when the welt(s) from the unintended mosquito fest seem out of control?

Family nurse practitioner Allison Folger, CNP, says mosquito bites are simply a nuisance for many but explains they can get infected if you don’t leave them be.

“Scratching the bite to the point of bleeding can open the door for a bacterial skin infection to develop,” Folger explains. “This commonly occurs in children whose nails are understandably dirty from playing outside, though it also happens in adults.”

The infection’s not the mosquito’s fault!

The infection, called cellulitis, is from bacteria that enters the punctured skin from your hands. Warning signs include:

• Swelling of the lymph nodes.
• A wide-spreading redness around the mosquito bite.
• Red streaking that extends beyond the initial bite.
• Pus or drainage.
• Area feels warm to the touch.
• Chills.
• Fever (above 100 F).

“If you or a child has these signs of infection, it is important to see your doctor,” Folger says. One easy way to tell if the bite is spreading? Take a pen and draw an outline around the mosquito bite. That’s a fool-proof, objective way to keep an eye on it.

If your doctor confirms it’s cellulitis, you’ll need a round of antibiotics to kill the bacteria (typically strep (streptococcus) or staph (staphylococcus).

How to treat it in the meantime?

If you’ve got a mandarin orange-sized welt that you’re worried about, here’s the best way to treat it: Folger recommends cleaning the bite with soap and water, and then applying an over-the-counter hydrocortisone cream. This will help reduce the swelling and itching.

If desired, this can be followed with calamine lotion, which contains a mild topical anesthetic that may ease the discomfort.

“Use ice packs on the area to help bring the inflammation down, and reapply the topical medication every four hours,” she recommends.

Your healthcare provider may also recommend using an oral antihistamine (such as Benadryl®), as they’re more effective at providing relief than topical creams.

Infected or just a itchy aggravation? You’ll probably be fine soon with proper care either way, Folger says. And getting bitten so badly may just remind you to take an ounce of prevention next time.