It’s Only Skin Deep: Recommendations for Skin and Soft Tissue Infections

August 6, 2021

Guest host Dr. Gabi Hester talks with Dr. Courtney Herring, pediatric hospitalist, about the diagnosis and management of skin and soft tissue infections.


Dr. Angela Kade Goepferd: This is talking pediatrics, a clinical podcast by Children’s Minnesota, where the complex is our every day. Each week, we bring you intriguing stories and relevant pediatric healthcare information. As we partner with you in the care of your patients. Our guests, data, ideas, and practical tips will surprise, challenge and perhaps change how you care for the most amazing people on earth, kids. Welcome to Talking Pediatrics. I’m your host, Dr. Angela Kade Goepferd. It’s summer and with summer comes lots of scrapes and bumps and bruises. It seems fitting then that on this episode of Guidelines with Gabi, Dr. Gabi Hester digs into the diagnosis and management of skin and soft tissue infections with guest Dr. Courtney Herring, pediatric hospitalist.

Speaker 1: Welcome to Guidelines with Gabi.

Dr. Gabi Hester: Erysipelas, cellulitis, impetigo, boils, pustules, folliculitis, furuncles, carbuncles, abscess, rubor, calor, tumor, dolor. The classic four signs for skin and soft tissue infection are well-known to medical providers, but not all kids will manifest redness of their skin, nor will they all have warmth, swelling, or pain.

Today, I get to talk with my friend and colleague, Dr. Courtney Herring, pediatric hospitalist, and med-surg co-medical director at Children’s Minnesota. We’re going to dig deep into the world of skin and soft tissue infections, how to recognize them and how to treat them. Courtney, thanks for joining.

Dr. Courtney Herring: Thanks, Gab. I really appreciate the invitation. Excited to be here.

Dr. Gabi Hester: So Courtney, take me to the very beginning. What is a typical presentation for kids who have skin and soft tissue infections?

Dr. Courtney Herring: Well Gabi, your introduction really nailed this one. Signs of cellulitis include color change of skin, warmth and even swelling over generally a localized area. And the affected area can be quite painful. Systemically, one may have fevers and chills related, but many may not. The lower extremities are the most common region of the body affected, typically unilaterally. However, wherever there is skin, infection can occur. So certain bacteria can also cause pus to collect beneath the skin, which we refer to as abscess or abscesses, and even create certain types of blisters called bullae. So for learners who are on the line, who enjoy crafting mnemonics, really a very non-innovative one is SPEW or S-P-E-W for swelling, pain, erythema or skin change, and warmth.

Dr. Gabi Hester: You mentioned some organisms can cause more purulence than others. What are the common culprits as far as pathogens go?

Dr. Courtney Herring: Well, many different bacteria actually can cause cellulitis, but the most common are really situated to two major genuses or genera, which are streptococci and staphylococci. Now, when we think of streptococci, we think of beta hemolytic streptococci, which we lovingly refer to as Group A strep and other in that family. And then in regards to staphylococci, we think in general staphylococcus aureus being the two main genuses that we deal with in cellulitis and skin and soft tissue infection.

Now these both are ubiquitous and can be found as common skin flora, and specifically when we’re taking care of young or adults with atopic dermatitis or eczema. And so in general, cellulitis is just a function of the integrity of the skin barrier becoming compromised and then complicated by what I lovingly call opportunistic sabotage.

Dr. Gabi Hester: And within staph aureus there a couple of different categories there. Can you talk to me a little bit about MRSA and its role in SSTI or skin infections?

Dr. Courtney Herring: Absolutely. You can’t talk about cellulitis without talking about the resistance that has been more apparent over the last several decades in healthcare. So MRSA or methicillin-resistant Staphylococcus aureus, or MRSA as we love to call it, it’s a growing problem that we’ve had across the nation. And in populations in the United States, specifically ours, we’ve actually been fortunate at Children’s Minnesota locally to look at our own microbiology and see exactly what we can treat appropriately for MRSA. Because the treatment is different. When you have a sensitive staphylococcal species, in general, we can use different types of antibiotics. So it is important to understand not only your community-based resistant pattern, but also understand what antibiotics you’re going to utilize for a sensitive versus resistant staph infection.

Dr. Gabi Hester: Courtney, I know you’re a hospitalist, but let’s put a different hat on for a minute and pretend that you’re in the outpatient setting, you’re a primary provider out in clinic. What are some of the red flags that you would be looking out for in these patients?

Dr. Courtney Herring: Well, that’s a great question because in general, SSTIs start and stay in an ambulatory setting. So cellulitis is a great classic example of diagnosing by a physical examination with pertinent history around trauma exposures and even clinical progression. So this is crucial in differentiating simple SSTIs from other morbid etiologies.

For primary pediatricians and/or providers, some patients are at increased risk of cellulitis or complication, especially those with chronic swelling, like lymphedema, those who are even morbidly obese have an increased risk of SSTIs. And beyond that, with other comorbidities including poorly controlled diabetes, for a provider in a clinic setting or an ambulatory setting, you’re really looking at is the patient demonstrating rapid progression of these processes or systemic signs of illness or even sepsis.

Other things that I know a lot of our community providers are so good at are also looking at barriers to outpatient care, which may or may not include surgical intervention like incision and drainage, which we can talk about more, but also just appropriate antibiotic coverage and ability to receive such coverage to ensure that you’re treating the infection.

Dr. Gabi Hester: There are a couple of great studies published on the evidence behind not getting blood cultures in kids with SSTI. For example, Malone & colleagues published in pediatrics in 2013, a study where they looked at over 400 immunocompetent kids who were admitted to a children’s hospital with uncomplicated SSTI. And none of those patients had a positive blood culture. But even just getting a blood culture in that study was associated with a higher length of stay, an average of almost a day in that study. And there was a subsequent study from Spain that had similar findings as well. I know you’re working on our Children’s Minnesota SSTI guideline. So what is reflected in that? What are the recommendations?

Dr. Courtney Herring: Well, the short answer, Gabi, is none. No labs. In general, 90 to 95% of medical visits related to SSTIs are considered ambulatory in nature. Patients are seen and subsequently discharged from a clinic and urgent care, or even an emergency department. For immunocompetent children, their risks are low if diagnosed and treatment is started in a timely manner, therefore labs don’t provide really any relative supplementation for clinical decision making.

Dr. Gabi Hester: Beyond even just limiting blood cultures, really there’s not a great role for CBC with differential or CRP or other inflammatory markers in the majority of cases. Is that what I’m hearing?

Dr. Courtney Herring: Absolutely. In the majority of cases you’re looking at not gaining anything by the blood draw at large. Because it’s not going to change in general, how you treat empirically and then potentially with targeted treatment downstream.

Dr. Gabi Hester: And I know our clinical guideline really excludes some of the more complex or complicated SSTI, thinking about burns or trauma or recent surgery immunocompromised. So I think it’s important to point that out, that there’s a caveat there. In those kids, we probably want to consider labs and a different management plan, but we’re talking today really about the uncomplicated patients who are otherwise well. Is that right?

Dr. Courtney Herring: Absolutely. I couldn’t agree more. If you have a history that includes trauma, immunocompromised states, you’re looking at a different field of treatment planning. And so when you have those instances, even in a clinic setting, you want to make sure that you’re doing due diligence. But in general, the overwhelming majority of patients are going to be fitting into a box of uncomplicated SSTI. And in that setting, there is no role in regards to having any laboratory values at your side.

Dr. Gabi Hester: Even in hospitalized kids who are med-surg status, for example?

Dr. Courtney Herring: I’m shaking my head, which no one can see on the podcast, but the answer is absolutely. I think there’s definitely obvious reasons that a child or young adult should be brought into our hospital for continued monitoring of a presumed SSTI. But those all don’t follow through that you actually need laboratory values to bring them in to hospitalize and monitor them.

Dr. Gabi Hester: So when should you get a blood culture?

Dr. Courtney Herring: There had been multiple studies that have shown that blood cultures rarely demonstrate true pathogenic bacterial growth, and even positive cultures don’t change clinical management. This specifically is a call-out to immunocompetent individuals. However, in any immunocompromised patient or any patient with clinical signs of sepsis, blood culture should be considered.

I kind of reference always back to the Infectious Disease Society of America, or IDSA, which recommends blood tests for patients with soft tissue infection who have signs and symptoms as they relate to a systemic toxicity. One being a blood culture, but they also call out the complete blood count, or CBC with differential. And then they also bring into a guidance around looking at general inflammatory processes and end organ concerns such as a C-reactive protein and levels of creatinine, bicarbonate, and even creatine phosphokinase in the setting of muscle involvement and breakdown.

Dr. Gabi Hester: You mentioned before two categorizations, broadly of SSTI. A purulent category and sort of a non-purulent category. Can you walk me through how we would treat patients in these different categories. Understanding that the exact antibiotics might differ depending on where you are in the country and your prevalence, but walk me through the treatment.

Dr. Courtney Herring: So for non-purulent cellulitis or skin and soft tissue infection, treatment is antibiotics. With presumptive coverage of gram-positive organisms, as we discussed earlier this session. Without automatically empirically targeting MRSA, unless there is an indication, to do so such as past MRSA infection or strong history of contact.

Moving off non-purulent to purulent SSTIs or with abscess, surgical incision and drainage is the primary therapy. This has been a consistent recommendation. However, there has been a dogma around it being the only treatment needed, and that principle has slowly evolved over the last decade. So in regards to antibiotic therapy, there’s a great 2018 study that is kind of a rapid recommendations group that looked at recurrence rates and/or failure of treatment in patients post-incision and drainage who either received or didn’t receive post-procedure antibiotics, as well as MRSA or non-MRSAC targeted therapy by reviewing several randomized controlled trials on these topics. And the results were summarized via clinical guidance, that supported targeted MRSA antibiotic treatment post I&D. And that’s something that we definitely leaned into in this revisionary work we’ve done on the SSTI guidelines here at Children’s this year.

Dr. Gabi Hester: Is there a role for shared decision-making in that process?

Dr. Courtney Herring: In general, there is typically room for shared decision-making. I think in this process at large, when you’re really going for a primary treatment of an incision and drainage in the setting of an abscess, I believe the primary provider really should be able to look at the individual patient, look at the clinical context, and whether with consideration of the patient, having education or family, having education around it, look to see if they feel like antibiotics would be fruitful for this particular patient.

However, this is a weak recommendation in regards to MRSA targeted therapy post I&D. However, there are other randomized controlled trials talking about the use of antibiotics post I&D, and the number needed to treat is actually pretty good. It’s around one in 10 for a lot of things. So that’s not bad odds when you look at making sure that you’re not having recurrence or failed treatment. So shared decision-making is always something that should be considered in our line of work in healthcare.

Dr. Gabi Hester: Tell me a little bit about duration of this antibiotic therapy. How long do kids need to be on antibiotics?

Dr. Courtney Herring: I love this question because stewardship is not only about having the most narrow coverage of the affected site or infection type, but it’s also about how actually long and how much antibiotic do you actually need. So as part of our most recent revisions, again, to the guidelines, we have modified duration of therapy recommendations regarding uncomplicated cellulitis. And that includes purulent infections post I&D, to a total duration of five days of antibiotic treatment.

The caveat is regarding when a patient requires hospitalization for treatment and maybe continued monitoring of presumed SSTI. At this junction, clinical improvement guides us to antibiotic duration with a recommended call-out to five days post what we think of as initial clinical improvement. And in general, as a hospitalist, I think of that actually being as when I’m also coinciding with looking at discharge criteria being met. So in general, you’re looking at a post-discharge at about five days from your hospitalization of continued antibiotic care.

Dr. Gabi Hester: Courtney, we are both hospitalists. So I know we often encounter patients where they’re admitted to the hospital, they’re started on one antibiotic and maybe they don’t get better right away or things even look worse. Can you talk to me a little bit about how you explain that phenomenon to families or trainees of sometimes things looking worse before they get better?

Dr. Courtney Herring: In reference to that failed treatment, question mark. So as a hospitalist, it’s a little bit a bane of our existence, because we have to be patient and we have to also exude the same patience that we can relate to our patients and families around that therapy in general is very targeted even in an empiric state. So when you’re looking at kind of progression, and I think of progression being really a lot of growth of skin changes. So whether it’s redness or skin changes that, depending on your skin tone, that actually is one of the monikers of really Group A strep and streptococci specifically. They’re buggers. They love to continue to have a very fulminant exotoxin release, which has a fulminant cytokine release involved that really continues the process of physical changes.

That does not mean your treatment has failed. And so we actually did call this out in our guidelines. As long as the patient has remained clinically stable beyond the focus of signs of infection, then you would really wait out for about 36 hours in the setting of a non-purulent based cellulitis. Given that streptococci are a presumed kind of first pass infection in regards to non-purulent cellulitis. In regards to purulent infections, we actually think more of the staphylococcal species. It’s not that it couldn’t be streptococci, but it’s not the typical. And so in general, post I&D, it’s a completely different trajectory once you’ve had surgical intervention. So very much a call-out to a non-purulent form of cellulitis.

Dr. Gabi Hester: I know everybody has different strategies or styles. I like to warn families and caregivers sort of in advance when we’re starting therapy that, particularly in those non-purulent situations, we may see extension of the color changes or the warmth as swelling can shift as well. Just so they’re anticipating that on the front end, and I think that’s important for outpatient providers to do as well. And it’s probably a good thing for us to keep in mind as far as our antimicrobial stewardship goes, that we’re not changing antibiotics before it’s truly indicated.

Dr. Courtney Herring: You’re hitting everything and the focus of what we really are trying to do here at Children’s with revising these guidelines.

Dr. Gabi Hester: Thank you so much, Courtney, for joining me today. It was so fun talking with you about skin and soft tissue infections. I also want to thank you for all the work you’re doing in leading this guideline revision. It’s a huge process, and we’re excited to have this effort that you’re leading.

Dr. Courtney Herring: Yeah. Again, this is great. It’s a joy for both of us. I appreciate you.

Speaker 1: Take-home points.

Dr. Gabi Hester: Number one. Skin and soft tissue infections often present with some combination of change in skin appearance, swelling, warmth, tenderness, and at times with drainage. Number two. Blood tests are not typically indicated in patients with uncomplicated skin or soft tissue infections. Number three. Incision and drainage is the main treatment for abscesses. Number four. Antibiotic therapy should be targeted to your local antibiogram as well as to the purulent versus non-purulent characteristics for your particular patient.