Tag: MRSA

Nurse documenting examination of patient's reddened lower leg

Cellulitis – a soft tissue/skin infection – is it MRSA?

On By Dr. Scott RennieIn Skin & Wound CareLeave a comment
IMG_5864Cellulitis is an infection of the skin and soft tissues.  It is common and most often it’s caused by bacteria that normally live on the skin.  These bacteria don’t normally cause any problems unless the skin is scratched, torn or punctured.  The most common bacteria that cause cellulitis are streptococci “Strep” or staphylococci “Staph.” Most of the time cellulitis is mild and heals with the use of antibiotics, however it can become severe and cause an infection that spreads throughout the body if left untreated.  It can also lead to deep infections called abscesses. Risk factors: 1)   Chronic skin condition such as eczema or psoriasis 2)   Accumulation of fluid (edema) due to poor circulation possibly from heart failure, liver disease, or removal of lymph nodes 3)   Recent injury, wound, cut or laceration to the skin 4)   Current skin infection such as athlete’s foot or impetigo 5)   Being overweight Symptoms:  Pain, tenderness, increased warmth, redness and swelling in a distinct area of skin.  The skin can be smooth and shiny in this area.  Fever and chills are not usually present. Other skin infections:  different kinds of infections that can be confused with cellulitis include an abscess or boil.  These are different because they are usually bumpy, raised and filled with pus.  Abscesses are usually caused by a staph bacteria which may be MRSA.  Cellulitis is more commonly caused by “strep” bacteria. Treatment:  We commonly use antibiotics and also treat the underlying problem that caused the skin infection (such as athlete’s food or increased edema, eczema or psoriasis) if present. Keeping the area elevated to reduce inflammation is also helpful.  It is important to keep the infected area clean and dry.  Showering or bathing can be done normally, but pat the area dry with a clean towel afterwards to dry the area completely.  You can also use a bandage or gauze to protect the skin if needed. Antibiotics are often used and will be tailored to the individual patient.  The patient’s specific area of infection, medical history, history of allergies and examination will be important in determining the proper antibiotics to use.  Sometimes the antibiotics will need to be given by IV in more serious cases of cellulitis. Treatment time:  In most cases, the swelling, warmth and redness should improve within 1-3 days after starting the antibiotics.  We often use a Sharpie marker and draw a circle around the area of redness so that we can examine the red area over a few days to see if it’s increasing, decreasing or staying the same.  Symptoms of redness and swelling can persist for up to 2 weeks but it should be gradually decreasing.  If it’s not improving, you should call or return to your health care provider for re-evaluation.   I hope that you have found this information useful.  Wishing you the best of health,

Cellulitis of the lower leg often starts at a crack or a small cut on the foot, and with diabetic neuropathy that break can go unnoticed until the whole leg is red. It is the reason I keep after people about the diabetic foot check and what to look for.

Updated for 2026: Pus or No Pus Decides the Antibiotic

The most useful thing I can add to this post is a distinction that was fuzzy in 2012 and is now the thing the whole treatment decision turns on. Is there pus, or is there not. If there is an abscess, a pocket of pus you can feel giving under your finger, that is usually staph, MRSA is on the table, and it needs drainage plus an antibiotic that covers MRSA. I have written about that separately. If it is plain cellulitis, meaning spreading red, warm, tender skin with no drainable pocket, that is usually strep, and a cephalosporin like cephalexin is the right drug. Adding MRSA coverage on top does not help, and this has been tested directly. Moran and colleagues randomized patients with uncomplicated cellulitis to cephalexin plus trimethoprim-sulfamethoxazole or cephalexin alone. Cure was 83.5 percent against 85.5 percent (1). No benefit, two drugs, more side effects. So if you have been handed two antibiotics for a red leg with no abscess, that is worth a conversation. The 2014 infectious disease guidelines remain the operative document here and have not been superseded (2).

Draw a Line Around It

This is the single most useful thing you can do, and it is more valuable to me on a video visit than almost anything else. Take a pen and trace the edge of the redness. Write the time next to it. Then photograph it. When we talk tomorrow, or if you end up in an urgent care instead, that line answers the only question that really matters, which is whether this is advancing, holding, or retreating. Redness that has crossed well past the line in a few hours is a different problem from redness that has not moved. Without the line, everyone is guessing from memory, and memory is bad at this.

What I Can and Cannot Tell From a Screen

I can see color, extent, and whether there is an obvious pocket. I can ask about fever, chills, how fast it came on, whether there was a break in the skin, and how your blood sugars have been. What I cannot do is feel it. Warmth and firmness are things I am taking your word for, and the difference between cellulitis and something deeper and far more dangerous is partly a matter of how the tissue feels and how much pain there is relative to how it looks. That last one matters. Pain out of proportion to the appearance is a red flag I take seriously, and it is a reason for me to send you in rather than treat from here. Good photographs help more than people expect. Natural light, the same angle each time, and something for scale.

When To Be Seen, Today

Fever or chills. Redness advancing visibly past your marked line. Pain that seems far worse than the skin looks, or skin that is dusky, blistering, or numb. Cellulitis on the face. Any of this in someone diabetic, immunosuppressed, or with poor circulation. And no improvement after forty eight hours on the right antibiotic. The rapidly advancing, severely painful ones are surgical emergencies, not prescriptions, and they are the reason I would rather over-refer than under-refer on this particular condition.

The Bottom Line

No pus means a cephalosporin, and adding a second antibiotic for MRSA does not improve anything. Pus means drainage. Draw a line around the redness and note the time, because that line is the best data anyone will have.

Sources

1. Moran GJ, et al. Effect of Cephalexin Plus Trimethoprim-Sulfamethoxazole vs Cephalexin Alone on Clinical Cure of Uncomplicated Cellulitis. JAMA. 2017;317(20):2088-2096. https://jamanetwork.com/journals/jama/fullarticle/2627970 2. Stevens DL, et al. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update. Clin Infect Dis. 2014;59(2):e10-e52. https://www.idsociety.org/practice-guideline/skin-and-soft-tissue-infections/

Related Reading

Abscesses and MRSA: What To Do About a Skin Infection Am I Truly Allergic to Penicillin? When to Use Telemedicine vs. Urgent Care: How I Spot the Sick One Scott Rennie, D.O.
Board Certified in Obesity Medicine and Family Medicine

This blog is for educational purposes only and does not constitute individual medical advice. Always consult your own physician before making changes to your health, medications, or treatment plan.

A clinician in scrubs and gloves preparing a length of sterile gauze for a dressing.

Abscesses – What to do about MRSA (Methicillin-resistant Staphylococcus aureus)

On By Dr. Scott RennieIn Skin & Wound Care9 Comments
IMG_5872“Staph” infections are most often caused by the organism Staphylococcus aureus, a bacterium that is carried on the skin of about 30% of healthy individuals.  Most of the time, these bacteria do not cause any symptoms. They just hang out on the skin because the skin is a natural layer of defense against infections.  If the skin is damaged, even from a small scratch however, Staph can cause anything from a mild skin infection to a severe, life-threatening illness, especially in young children or older adults. The difference between normal Staph infections and MRSA Infections:  Staph infections in the past were treated with antibiotics such as penicillin.  Some strains of Staph have unfortunately become resistant to penicillin and related antibiotics.  These strains of MRSA cannot be cured with traditional penicillin-related medications.  MRSA is now found in up to 70% of people in the community with a diagnosed staph infection. The spread of MRSA:  Many people become “colonized” with MRSA and that means that they carry the bacteria on their skin or in their nose.  It doesn’t cause any problems unless there is an opening in the skin from a scratch or cut.  You can become colonized with MRSA bacteria in several ways: 1)   Touching the skin of someone else who has been colonized with MRSA 2)   By touching or inhaling small droplets from breathing, coughing or sneezing 3)   By touching a contaminated surface such as a phone headset, countertop or door handle Community MRSA:  You can more easily pick up MRSA by: 1)   Being overweight or obese 2)   Shaving body hair 3)   Sharing personal items or equipment that is not cleaned 4)   Skin trauma such as turf burns, cuts or sores 5)   Physical contact with someone with a draining cut or sore that has MRSA Symptoms:  A skin infection is the most common symptom and it may be mistaken for a spider bite.  A raised, red lump that is tender or cluster of  “pimples,” or large tender lump that drains pus may also be present.  If the bacteria enter the bloodstream, it is possible to develop an infection in areas other than the skin.  A staph infection can occur in a heart valve, inside a bone, a joint or in an implanted device such as an IV line, pacemaker or replacement joint.  Symptoms of these types may include fever, fatigue as well as swelling in the infected area. Diagnosis:  To actually diagnose a true MRSA infection, a culture of the infected area must be performed.  A small sample of bacteria or pus collected from the skin or bloodstream is collected and allowed to grow in an environment that the bacteria thrive in, and then we test these bacteria for resistance to certain antibiotics, including penicillin. Treatment:  in patients with community acquired MRSA we use antibiotics that may be different than patients who develop MRSA in the hospital.  This is because community acquired MRSA is usually sensitive to antibiotics such as Bactrim, clindamycin, or doxycycline.  MRSA that is acquired in the hospital often has to be treated with antibiotics given through an IV such as Vancomycin. A surgical procedure called an I&D (incision and drainage) can be done to drain the pus and heal the infection. If you’ve had an incision and drainage done at your doctor’s office:  After having a surgical procedure done at your doctors office, the wound is often packed with sterile gauze to allow the wound to heal from the bottom upwards.  This way, the wound doesn’t close up at the top and leave a space underneath the top of the skin where bacteria can start growing and cause an infection.  This type of wound needs special attention and observation each day. Basics of wound care after an I&D (incision and drainage): 1)   Keep the bandage/wound clean and dry. 2)   Only remove the bandage to clean around the wound and follow the advice of your medical provider on how to do this. 3)   The packing gauze should be removed little by little until the wound heals completely.  The decision on how much to remove (if any) should be made by a medical provider but this can be explained to the patient on an individual basis (ie. Wounds heal differently depending on the situation). 4)   You may need to wear a splint to decrease movement to the area and allow wound healing. 5)   Antibiotics and pain medication may be prescribed. Prevention:  The CDC has made several recommendations about how to prevent and control MRSA in our communities: 1)   Wash hands with soap and water paying special attention to the fingernails, wrists and between the fingers. 2)   If a sink is not available, alcohol-based hand sanitizers are a good alternative. 3)   Cover all cuts and scrapes and keep them clean until healed. 4)   Don’t touch wounds or bandages from other people 5)   Avoid sharing towels, razors, clothing, uniforms, towels, brushes, combs, make-up and towels. 6)   Athletes should shower after every sports activity and use soap and clean towels. 7)   Exercise equipment at sports clubs and schools should be wiped down with an alcohol-based solution after using it. Care for family members:  Our guidelines do not recommend that family members with MRSA be treated with antibiotics.  Proper preventative measures as described above, should be used. Should I be tested?:  Experts do not recommend widespread testing for MRSA because of the small risk of infection.  Currently only 4 out of 10,000 people in our communities develop a MRSA infection per year.   I hope that you have found this information useful.  Wishing you the best of health,

Recurrent boils and abscesses are one of the reasons I end up asking about someone’s blood sugar, since diabetes both invites skin infections and slows the healing after they are drained. If that is where you are, start with what a new diagnosis of type 2 diabetes actually means. Most of my writing now is obesity and metabolic medicine, including what Wegovy and Zepbound cost without insurance.

Updated for 2026: What Has Changed Since I Wrote This

I first published this in 2012. Most of it held up. One part did not, and the change matters enough that I would rather correct it here than leave it sitting. Back then the teaching was that a small abscess, once drained, did not need antibiotics. Drainage was the treatment. Antibiotics were for people who looked sick, ran a fever, or had redness spreading past the lump. That is what I wrote. It is what most of us were taught. Two randomized trials changed it. In 2016, Talan and colleagues published a placebo-controlled trial in the New England Journal of Medicine. Everyone got drainage. Half then got trimethoprim-sulfamethoxazole and half got placebo. Cure was 92.9 percent with the antibiotic against 85.7 percent with placebo (1). The following year Daum and colleagues ran a similar trial in smaller abscesses, adults and children together, comparing clindamycin, TMP-SMX, and placebo after drainage. Cure came in at 83.1 percent, 81.7 percent, and 68.9 percent. Clindamycin had fewer recurrences, 6.8 percent against 13.5 percent, and more diarrhea (2). Drainage still does the heavy lifting. But adding an antibiotic afterward buys a real, measurable improvement, and I now recommend it for most drained abscesses instead of holding it back for the ones who look ill. One limit worth knowing, because it cuts the other way. The benefit is specific to pus. In 2017 Moran and colleagues tested cephalexin plus TMP-SMX against cephalexin alone in uncomplicated cellulitis with no abscess. No difference, 83.5 percent against 85.5 percent (3). No pocket of pus, no reason to add MRSA coverage.

What This Actually Means on a Video Visit

I practice entirely by video, so let me be straight about what I can and cannot do with an abscess on a screen. I can look at it. I can ask you to press on it and tell me whether it feels like a firm knot or a soft pocket that gives under your finger. I can ask how fast it came up, whether you have had fever, how your blood sugars have been running. What I cannot do is drain it. If there is pus under there, somebody has to open it, and that somebody has to be in the room with you. So here is the honest version. Send me a photo of a red, painful, fluctuant lump and I am going to tell you it needs to be drained, and help you work out where to go. Once it has been drained, the antibiotic afterward is something I can handle from here without any trouble.

When You Need To Be Seen Today

Fever or chills. Redness spreading well past the edge of the lump. An abscess on your face, particularly near your eyes or nose. Poorly controlled diabetes, or a suppressed immune system. No improvement forty eight hours after drainage and antibiotics. Any of those and you belong in front of someone in person, not on a screen (4).

The Bottom Line

Cutting it open is still what fixes an abscess. The 2012 version of this post told you that was usually enough by itself. The evidence since then says an antibiotic afterward makes a real difference, and that is how I practice now.

Sources

1. Talan DA, et al. Trimethoprim-Sulfamethoxazole versus Placebo for Uncomplicated Skin Abscess. N Engl J Med. 2016;374(9):823-832. https://pmc.ncbi.nlm.nih.gov/articles/PMC4851110/ 2. Daum RS, et al. A Placebo-Controlled Trial of Antibiotics for Smaller Skin Abscesses. N Engl J Med. 2017. https://pmc.ncbi.nlm.nih.gov/articles/PMC6886470/ 3. Moran GJ, et al. Effect of Cephalexin Plus Trimethoprim-Sulfamethoxazole vs Cephalexin Alone on Clinical Cure of Uncomplicated Cellulitis. JAMA. 2017;317(20):2088-2096. https://jamanetwork.com/journals/jama/fullarticle/2627970 4. Stevens DL, et al. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update. Clin Infect Dis. 2014;59(2):e10-e52. https://www.idsociety.org/practice-guideline/skin-and-soft-tissue-infections/

Related Reading

When to Use Telemedicine vs. Urgent Care: How I Spot the Sick One Allergic Antibiotic Drug Reactions: Am I Truly Allergic to Penicillin? Cellulitis – a soft tissue/skin infection – is it MRSA? What is Hidradenitis suppurativa? Pilonidal Cysts – A pain in the rear Epidermal Inclusion Cysts Explained: What Are They? Scott Rennie, D.O.
Board Certified in Obesity Medicine and Family Medicine

This blog is for educational purposes only and does not constitute individual medical advice. Always consult your own physician before making changes to your health, medications, or treatment plan.

Microscopic glowing microbes of various shapes and colors against a dark background

Antibiotic Superbugs CRKP and MRSA: Who Is at Risk?

On By Dr. Scott RennieIn Infectious DiseaseLeave a comment
By Lisa Collier Cool Apr 07, 2011 Misuse of antibiotics has led to a global health threat: the rise of dangerous—or even fatal—superbugs. Methicillin-resistant Staphylococcus aureus (MRSA) is now attacking both patients in hospitals and also in the community and a deadly new multi-drug resistant bacteria called carbapenem-resistant Klebsiella pneumoniae, or CRKP is now in the headlines. Last year, antibiotic resistant infections killed 25,000 people in Europe, the Guardian reports. Unless steps are taken to address this crisis, the cures doctors have counted on to battle bacteria will soon be useless. CRKP has now been reported in 36 US states—and health officials suspect that it may also be triggering infections in the other 14 states where reporting isn’t required. High rates have been found in long-term care facilities in Los Angeles County, where the superbug was previously believed to be rare, according to a study presented earlier this month. CRKP is even scarier than MRSA because the new superbug is resistant to almost all antibiotics, while a few types of antibiotics still work on MRSA. Who’s at risk for superbugs—and what can you do to protect yourself and family members? Here’s a guide to these dangerous bacteria. Understanding different types of bacteria. What is antibiotic resistance? Almost every type of bacteria has evolved and mutated to become less and less responsive to common antibiotics, largely due to overuse of these medications. Because superbugs are resistant to these drugs, they can quickly spread in hospitals and the community, causing infections that are hard or even impossible to cure. Doctors are forced to turn to more expensive and sometimes more toxic drugs of last resort. The problem is that every time antibiotics are used, some bacteria survive, giving rise to dangerous new strains like MRSA and CRKP, the CDC reports. What are CRKP and MRSA? Klebseiella is a common type of gram-negative bacteria that are found in our intestines (where the bugs don’t cause disease). The CRKP strain is resistant to almost all antibiotics, including carbapenems, the so-called “antibiotics of last resort.” MRSA (methacillin-resistant staphylococcus aureus) is a type of bacteria that live on the skin and can burrow deep into the body if someone has cuts or wounds, including those from surgery. Who is at risk? CRKP and MRSA infects patients, usually the elderly—who are already ill and living in long-term healthcare facilities, such as nursing homes. People who are on ventilators, require IVs, or have undergone prolonged treatment with certain antibiotics face the greatest threat of CRKP infection. Healthy people are at very low risk for CRKP. There are 2 types of MRSA, a form that affects hospital patients, with similar risk factors to CRKP, and another even more frightening strain found in communities, attacking people of all ages who have not been in medical facilities, including athletes, weekend warriors who use locker rooms, kids in daycare centers, soldiers, and people who get tattoos. Nearly 500,000 people a year are hospitalized with MRSA. Keeping hospital patients safe. How likely is it to be fatal? In earlier outbreaks, 35 percent of CRKP-infected patients died, Journal of the American Medical Association (JAMA) reported in 2008. The death rate among those affected by the current outbreak isn’t yet known. About 19,000 deaths a year are linked to MRSA in the US and rates of the disease has rise 10-fold, with most infections found in the community. How does it spread? Both MRSA and CRKP are mainly transmitted by person-to-person contact, such as the infected hands of a healthcare provider. They can enter the lungs through a ventilator, causing pneumonia, the bloodstream through an IV catheter, causing bloodstream infection (sepsis), or the urinary tract through a catheter, causing a urinary tract infection. Both can also cause surgical wounds to become infected. MRSA can also be spread in contact with infected items, such as sharing razors, clothing, and sports equipment. These superbugs are not spread through the air. What are the symptoms? Since CRKP presents itself as a variety of illnesses, most commonly pneumonia, meningitis, urinary tract infections, wound (or surgical site) infections and blood infections, symptoms reflect those illnesses, most often pneumonia. MRSA typically causes boils and abscesses that resemble infected bug bites, but can also present as pneumonia or flu-like symptoms. How are superbugs related? The only drug that still works against the CRKP is colistin, a toxic antibiotic that can damage the kidneys. Several drugs, such as vancomycin, may still work against MRSA. What’s the best protection against superbugs? Healthcare providers are prescribing fewer antibiotics, to help prevent CRKP, MRSA and other superbugs from developing resistance to even more antibiotics. The best way to stop bacteria from spreading is simple hygiene. If someone you know is in a nursing home or hospital, make sure doctors and staff wash their hands in front of you. Also wash your own hands frequently, with soap and water or an alcohol-based hand sanitizer, avoid sharing personal items, and shower after using gym equipment. The CDC has reports on Klebsiella bacteria and MRSA, discussing how to prevent their spread and has just issued a new report on preventing bloodstream infections.

Scott Rennie, D.O.
Board Certified in Obesity Medicine and Family Medicine

This blog is for educational purposes only and does not constitute individual medical advice. Always consult your own physician before making changes to your health, medications, or treatment plan.