Cellulitis: skin infections and infected cuts

Cellulitis is a bacterial infection of the deeper layers of the skin. It is usually caused by staph or strep bacteria that get in through a wound, a cut, an insect bite, an animal bite, an ingrown toenail, a tattoo or cracked skin. It is not cellulite, the dimpled skin on the thighs, which is not an infection. It is most common on the legs and feet, and it generally does not spread from person to person.

The risk is higher if you have diabetes, poor circulation, long-term leg swelling, excess weight or a weakened immune system. The cracks from athlete’s foot can also let bacteria in.

In Puerto Rico, watch out for the sea: an open wound that goes into seawater or brackish water (where fresh and salt water mix) can get infected with Vibrio bacteria, which can be serious, especially if you have liver disease, diabetes, cancer or a weakened immune system. If you have a wound, stay out of the sea until it heals, or cover it with a waterproof bandage; if seawater gets in, wash it right away with soap and clean running water.

Doctor online 24/7: video doctor visits 24/7 — book online and choose your time right away. Every day, any time (Puerto Rico time).

A skin infection is handled in a doctor visit, the same price for every age, with no membership. You pay by card when you request the visit, and you get a full refund if the clinic can’t see you. It is part of our virtual urgent care. See all prices.

Signs of cellulitis start suddenly and can grow quickly in the first 24 hours:

• Red skin that keeps spreading
• Skin that is warm to the touch
• Swelling
• Pain or tenderness when touched
• Fever and chills in some cases

Cellulitis is treated with antibiotics. A mild infection is usually treated with an antibiotic by mouth, and most people improve in 7 to 10 days; finish the whole course even if you feel better. More serious infections, or infections in people with a weakened immune system, sometimes need IV antibiotics in a hospital. Keeping the leg or arm raised helps bring the swelling down.

Which antibiotic is used? Per the IDSA (Infectious Diseases Society of America) guideline, cellulitis without pus is usually caused by strep, and a common option by mouth is cephalexin (one well-known brand is Keflex), a cephalosporin antibiotic. Per MedlinePlus, cephalexin is used for certain bacterial infections of the skin, bones, ears, airways, genitals and urinary tract; it does not work for colds, flu or other viral infections. If there is pus or an abscess, the cause is usually staph, sometimes resistant staph (MRSA), and the main treatment is usually draining it; if an antibiotic is also needed, one that covers MRSA, such as trimethoprim-sulfamethoxazole, is used. If you are allergic to penicillin or another antibiotic, tell the doctor: cephalexin is related to penicillin. The doctor decides whether an antibiotic is appropriate for you, and which one; read more about antibiotics.

If needed, the doctor gives you an order for lab tests such as a blood count at a lab near you.

• Wash cuts and scrapes with soap and water and keep them covered until they heal.
• Don’t squeeze or pop a pimple or a bump full of pus.
• If you have diabetes, check your feet every day.

For your safety, go to the emergency room or call 911 if you have any of these signs. Don’t wait for a video visit.

• The red area spreads fast or passes the line you drew within a few hours
• Fever with chills, unusual sleepiness or confusion
• Red streaks spreading from the area, or blisters on the infected skin
• Very severe pain in the area
• Infection around the eye or on the face
• A wound that was in the sea and becomes red, swollen and painful
• Any skin infection if you have diabetes or a weakened immune system and you feel unwell