EM@3AM: Erysipelas

Answer: Erysipelas

Introduction/Etiology

• Erysipelas is a superficial infection of the dermis that may extend to the superficial cutaneous lymphatics^{3, 6, 10}
• Described as an area of sharply demarcated erythema with raised edges that most commonly affects the lower extremities (approximately 80% of cases) and face^{3, 5, 6, 10}
• Streptococcus pyogenes is the most commonly implicated organism^{1, 5, 6}

• Other organisms that have been reported but are rare include S. aureus(including MRSA), Klebsiella pneumoniae,  influenzae, E. coli, S. pneumoniae, S. pyogenes, and Moraxella species
• Infection often occurs from disruption of the skin^{1, 5, 10}
  • Erysipelas may extend via the lymphatic system, which explains why some patients have tender inguinal lymphadenopathy proximal to the affected leg

• Complications include thrombophlebitis, abscesses, and gangrene⁶
• Risk factors include lymphedema, obesity, leg ulcers, IV drug abuse, tinea pedis (from skin breakdown in the intertriginous space), poorly controlled diabetes (or other immunocompromised states), liver disease, nephrotic syndrome, AV fistulas, saphenous vein excision for bypass or radical mastectomy (i.e., due to lymphatic obstruction)^{3, 5}

Epidemiology

• Erysipelas can affect people of all age groups, races, and sex⁵
  • Some studies showed that erysipelas is more common in females
  • Peak incidence is reported to be in patients aged 60 to 80 years
• The incidence and prevalence of erysipelas has decreased with improved sanitation and the development of antibiotics, respectively ⁵

ED Evaluation

• Erysipelas is a clinical diagnosis and most cases do not require laboratory or imaging studies^{5, 10}

History and Physical

• Timing of symptoms and speed of progression^{3, 5, 6, 9}
• Assess comorbidities^{3, 5, 6, 9}
• Thorough exam looking for areas of skin breakdown that could account for a portal of entry
  • Assess the intertriginous areas of the toes for tenia pedis with skin breakdown¹

Differential Diagnosis

• Consider the following: necrotizing fasciitis, septic arthritis, clostridial myonecrosis, pyomyositis, compartment syndrome, toxic shock syndrome, cellulitis⁹
  • Red-flags include severe sepsis, septic shock, pain that is out of proportion to exam and a rapidly progressing infection
  • Always consider a more extensive work up in any ill-appearing patient (e.g., sepsis), immunocompromised patients, IV drug users, patients with prosthetic heart valves or any intravascular device
  • Clinical features may not abe enough to differentiate erysipelas from cellulitis, and in such cases the treatment should be targeted towards cellulitis

Labs

• No laboratory evaluation is required for the diagnosis of erysipelas. Labs are not necessary for otherwise healthy individuals without systemic symptoms ,as they do not change management^{3, 5}
  • Labs may show an elevated WBC, ESR, and CRP
• Blood cultures have a low yield (only positive in 5% of cases) but should be considered in those with prosthetic heart valves, artificial joints, and immunocompromised or toxic-appearing patients^{3, 5}

Imaging

• Imaging not usually indicated³
• May assist in identifying other causes when these are suspected (e.g., necrotizing fasciitis)^{3, 11}
  • Imaging is usually in the form of plain film X-rays, CT scans, ultrasound, or MRI and depend on the suspected pathology
• Ultrasound can be of utility when the diagnosis is in question as it may provide evidence of infections that affect deeper tissues (e.g., cobblestoning in cellulitis)¹¹

Treatment

• Most cases of erysipelas resolve without sequelae after appropriate antibiotic therapy.^{3, 9} The following are general recommendations for adult patients with normal renal function and may differ from local guidelines
• Some experts believe that when erysipelas affects the face covering for MRSA is indicated and that in cases where it affects the legs a penicillin or cephalosporin is sufficient¹¹
• The following are indications for MRSA coverage ⁹
  • Systemic signs of toxicity (fevers, tachycardia, hypotension)
  • Purulent drainage or exudate
  • Immunocompromised states (e.g., immunosuppressive drugs, chemotherapy)
  • Risk factors for MRSA infection (past infection, MRSA colonization, intravenous drug use, or recent healthcare exposure)
• Parenteral antibiotics covering for both beta-hemolytic streptococcus and S. aureus including MRSA should be given in any patient who has systemic symptoms, including the following:^{1, 5, 9, 12}
  • Fever greater than 100.4°F/38°C
  • Hypotension
  • Sustained tachycardia
  • Rapid progression of erythema (i.e., doubling of affected area within 24 hours)
  • Extensive erythema
  • Immunocompromised state
  • Inability to tolerate or absorb oral therapy
• The treatment for patients requiring parenteral antibiotics is the same as for cellulitis

Antibiotic therapy^{1, 3, 9, 12}

• Oral antibiotics that cover beta-hemolytic streptococcus

• Oral antibiotics that cover beta-hemolytic streptococcus and MRSA
  • Can be used in cases of beta-lactam allergy

• Another appropriate regimen used when MRSA is suspected is amoxicillin 875 mg orally twice daily (streptococcal coverage) plus doxycycline 100 mg orally twice daily (staphylococcal coverage including MRSA). However, this regimen is not to be used in patients with beta lactam allergies

• Parenteral antibiotics that cover beta-hemolytic streptococcus and MSSA

• Parenteral antibiotics that cover beta-hemolytic streptococcus and MRSA

• In recent years the FDA has also approved 3 antibiotics for the treatment of acute bacterial skin and skin structure infections, including oritavancin(Orbactiv), dalbavancin (Dalvance), and tedizolid (Sivextro)³
  • These agents cover MSSA, MRSA, S. pyogenes, S. agalactiae, among others
• Duration of antibiotic therapy is analogous to that of cellulitis. In general, 5 to 7 days is appropriate for uncomplicated cases. Extension of antibiotic therapy for up to 14 days may be needed in the setting of severe infection, slow response, or immunosuppression⁹
  • Symptomatic improvement is usually seen in 24 to 48 hours but visible improvement in skin manifestation can take 72 hours
• Adjunctive treatments include cold compresses, analgesics, and elevation of the affected limb^{5, 6, 9}
• Tinea pedis may cause skin breaks that becomes a site of entry. ¹ These require topical antifungal treatment in addition to the appropriate antibiotic regimen that covers for erysipelas. Oral or IV antifungals are seldom indicated ⁶
  • Topical terbinafine or imidazole two times daily for 2-3 weeks⁴
  • Absorbent antifungal powder containing aluminum chloride⁴
  • Always keep the areas dry and avoid tight fitting clothing⁴
• Surgical consultation for debridement if there is gangrenous or necrotic tissue^{5, 6}

Case Resolution

The patient received appropriate parenteral antibiotics with great response. The patient reported feeling better, pain and other symptoms were well controlled 24 hours after starting antibiotics and pain medication. The infection began to subside 72 hours after starting therapy. During her admission, an MRI was ordered and was negative for osteomyelitis. Cultures did not grow any organisms. Wound care was consulted for management of her ulcer. The patient was subsequently discharged home and had made marked improvement on subsequent follow up.

Pearls and Pitfalls

• Erysipelas is a superficial infection that most commonly affects the lower extremities and is often caused by Group A Streptococcus infection
• Laboratory work up is often not necessary and does not change management in otherwise healthy patients. However, it must be considered in toxic-appearing patients, those with prosthetic heart valves, artificial joints, or immunocompromised states
• Clinicians must keep a broad differential and consider other conditions such as necrotizing fasciitis, clostridial myonecrosis, compartment syndrome, toxic shock syndrome, etc.
• Always inspect the feet for evidence of fungal infections as these may cause skin breakdown that could be the primary portal of entry
• Choose parenteral antibiotics for those with systemic symptoms, rapid progression of erythema, immunocompromised states or inability to tolerate oral therapy