Erysipelas

Erysipelas is an acute, non-purulent infection of the superficial dermis and lymphatics, predominantly caused by beta-hemolytic streptococci (primarily Group A Streptococcus), presenting as a sharply demarcated, bright-red, raised plaque with systemic symptoms. [1-2] It most commonly affects the lower extremities (~76–85%) and the face (~17%). [3-4]

1. History

• Onset and progression: Acute onset of a well-demarcated, painful, warm, red area — often preceded by constitutional symptoms (fever, chills, malaise) before the erythema appears. In one study, 91.4% of erysipelas patients reported constitutional symptoms at or before erythema onset. [5]
• Entry portal: Ask about recent skin breaks — wounds, insect bites, tinea pedis, leg ulcers, eczema, surgical sites, IV drug use. [6-7]
• Timing: Rapid spread over hours to days; tongue-like extensions are characteristic. [1]
• Prior episodes: Recurrence rate is 8–20% annually; up to 40% lifetime recurrence. Ask about number and location of prior episodes. [8-9]
• Associated symptoms: Fever, rigors, malaise, nausea. Systemic symptoms may precede skin findings by hours. [9]
• Important negatives: Purulent drainage (suggests abscess/cellulitis), pain out of proportion (necrotizing fasciitis), crepitus, skin necrosis, numbness.

2. Alarm Features

• Pain out of proportion to exam findings → necrotizing fasciitis [2][10]
• Rapidly spreading erythema with dusky/violaceous discoloration, bullae, skin necrosis, or crepitus [10-11]
• Hemodynamic instability — hypotension, tachycardia, altered mental status (SIRS/sepsis) [9]
• Cutaneous numbness or anesthesia over the affected area
• Failure to improve within 48–72 hours of appropriate antibiotics [5]
• Immunocompromised host (chemotherapy, neutropenia, HIV) with rapidly progressive infection [9]

3. Medications

• First-line treatment: Penicillin — erysipelas responds reliably (98.3% within 2 days). Penicillin V 500 mg PO QID or amoxicillin 500 mg PO TID for outpatient; IV penicillin G for inpatient. [1][3][5][9]
• Alternatives (penicillin allergy): Cephalexin 500 mg PO QID, clindamycin 300–450 mg PO TID, or macrolides (azithromycin, erythromycin). [9][12]
• Duration: 5 days per IDSA, extended if no improvement. [9][13]
• IV options: Penicillin G 2–4 million units IV q4–6h; cefazolin 1–2 g IV q8h. [9]
• MRSA coverage is generally unnecessary for classic non-purulent erysipelas. Add MRSA coverage only if purulent drainage, penetrating trauma, IVDU, MRSA colonization, or SIRS. [9]
• Recurrence prophylaxis: Penicillin V 250 mg PO BID for ≥2 episodes/year; reduces recurrence by ~69% while on therapy (NNT = 6). [14-15]
• Medication contributors: Immunosuppressants (corticosteroids, biologics, chemotherapy) increase susceptibility.

4. Diet

• No specific dietary triggers for erysipelas.
• Hydration is important during febrile illness.
• Long-term: Weight management is relevant, as obesity is an independent risk factor for both primary and recurrent erysipelas. [4][6][16]

5. Review of Systems

• Constitutional: Fever, chills, rigors, malaise, fatigue (present in majority) [3][5]
• Skin: Erythema, warmth, swelling, pain, vesicles/bullae, lymphangitic streaking
• Musculoskeletal: Joint pain/swelling near affected area (rule out septic arthritis, gout)
• Vascular: Unilateral leg swelling (consider DVT — prevalence ~2–3% in lower extremity erysipelas) [17-18]
• Endocrine: Diabetes symptoms (polyuria, polydipsia) — diabetes is a key comorbidity [4][16]

6. Collateral History and Family History

• Prior episodes of erysipelas/cellulitis — location, frequency, treatments used
• Surgical history: Lymph node dissection (axillary for breast cancer, inguinal), saphenous vein harvest, radical pelvic surgery — all predispose to lymphedema and recurrence [7][19]
• Social context: Homelessness, IVDU, living conditions [9]
• Family history is generally not a major contributor, though familial lymphedema syndromes (e.g., Milroy disease) may predispose.

7. Risk Factors

• Disruption of cutaneous barrier — the strongest risk factor (OR 23.8): leg ulcers, wounds, tinea pedis/toe-web intertrigo, eczema, psoriasis [6]
• Lymphedema (OR 71.2 in one case-control study) [6]
• Venous insufficiency (OR 2.9) [6]
• Leg edema from any cause (OR 2.5) [6]
• Obesity (OR 2.0) [4][6][16]
• Diabetes mellitus [4][16][20]
• Prior episode of erysipelas/cellulitis [9][14]
• Prior surgery with lymphatic disruption [7][16]
• Immunosuppression [14]
• Tinea pedis — population attributable risk of 61% for leg erysipelas [6]

8. Differential Diagnosis

• Cellulitis — deeper, poorly demarcated, darker red, less likely to have early constitutional symptoms [1-2][5]
• Necrotizing fasciitis — pain out of proportion, dusky skin, crepitus, rapid progression, systemic toxicity; requires emergent surgical exploration [2][10]
• Deep vein thrombosis — unilateral leg swelling, erythema, calf tenderness; use Wells score and duplex ultrasound [17][21]
• Stasis dermatitis — bilateral, chronic, associated with hemosiderin deposition and varicosities; a common cellulitis mimic [2][21]
• Contact dermatitis — pruritic, well-demarcated, often bilateral; exposure history [21]
• Gout/septic arthritis — periarticular erythema and swelling; joint aspiration differentiates [21]
• Abscess — fluctuant collection; point-of-care ultrasound differentiates [2]
• Erythema migrans (Lyme) — expanding annular erythema with central clearing; tick exposure history
• Herpes zoster — dermatomal, vesicular, painful

9. Past Medical History

• Prior erysipelas/cellulitis episodes (strongest predictor of recurrence) [9][14]
• Lymphedema (primary or secondary) [6][19]
• Venous insufficiency, chronic leg edema, varicose veins [6][20]
• Diabetes mellitus [4][16]
• Obesity [4][6]
• Cancer (especially breast cancer with axillary dissection) [4][7]
• Immunosuppressive conditions or medications [14]
• Chronic skin conditions (eczema, psoriasis, tinea pedis) [6][14]
• Saphenous vein harvest for CABG [7]

10. Physical Exam

• Vital signs: Fever (present in 25–77% depending on setting), tachycardia; hypotension and altered mental status suggest severe infection [2-3][9]
• Skin: Sharply demarcated, raised, bright-red, warm, tender plaque with tongue-like extensions; peau d'orange appearance from lymphatic involvement [1-2][9]
• Vesicles/bullae and petechiae/ecchymoses may develop in severe cases [9]
• Lymphangitis: Linear erythematous streaking proximal to the lesion [2]
• Regional lymphadenopathy: Tender, enlarged nodes draining the affected area [9]
• Interdigital toe spaces: Examine for fissuring, maceration, tinea pedis — a critical and often overlooked entry portal [6][9]
• Concerning findings suggesting necrotizing fasciitis: Dusky/violaceous discoloration, skin necrosis, crepitus, cutaneous anesthesia, pain out of proportion [2][10]
• Mark the borders of erythema with a skin marker to track progression.

11. Lab Studies

• Routine labs are not required for uncomplicated cases. [9]
• When obtained: Leukocytosis and elevated CRP are typical; CRP ≥ 3.27 mg/dL distinguishes erysipelas from limited cellulitis with 75% sensitivity and 73% specificity. [22]
• Elevated ESR found in ~60% of cases. [3]
• Blood cultures: Positive in ≤5% of cases; obtain only if systemic toxicity (high fever, hypotension), immunocompromised, malignancy, or unusual exposures. [9]
• Wound/aspirate cultures: Not routinely recommended; consider in immunocompromised patients, animal bites, immersion injuries. [9]
• To rule out dangerous conditions:
  • WBC > 15,400/μL or Na < 135 mmol/L → raises concern for necrotizing fasciitis [10]
  • Lactate, CK, coagulation studies if necrotizing infection suspected
  • BMP for renal function (antibiotic dosing)

12. Imaging

• Imaging is generally unnecessary for uncomplicated erysipelas. [9]
• Point-of-care ultrasound: Useful to rule out abscess (anechoic/hypoechoic fluid collection) or DVT. [2][21]
• CT with contrast: If concern for necrotizing fasciitis — may show fascial thickening, gas tracking, or fluid along fascial planes. However, imaging should not delay surgical exploration if clinical suspicion is high. [10]
• MRI: Most sensitive for deep soft tissue infection and necrotizing fasciitis, but rarely needed acutely.
• Duplex ultrasound: Consider if clinical concern for DVT (unilateral leg swelling disproportionate to erythema). [17-18]

13. Special Tests

• LRINEC Score (Laboratory Risk Indicator for Necrotizing Fasciitis): Based on WBC, hemoglobin, sodium, glucose, creatinine, and CRP. Score ≥ 6 has PPV 92% and NPV 96% for necrotizing fasciitis vs. cellulitis in the index study. Use as an adjunct — clinical judgment remains paramount. [10]
• Wells Score for DVT: Apply if DVT is in the differential; pooled DVT incidence in erysipelas/cellulitis is low (~2–3% for proximal DVT), comparable to low-risk Wells patients. [17-18]
• Skin marking: Outline the erythema border with a marker and timestamp — a simple but critical bedside tool to track progression or response to therapy.
• Bedside ultrasound: Cobblestoning of subcutaneous tissue supports soft tissue infection; fluid collection suggests abscess.

14. ECG

• ECG is not routinely indicated for erysipelas.
• Obtain if sepsis is suspected (tachycardia, hypotension) or in patients with cardiac comorbidities.
• Consider ECG in patients with atrial fibrillation or other cardiac conditions that may affect management (e.g., anticoagulation decisions). [4]

15. Assessment

Erysipelas is a clinical diagnosis based on the characteristic sharply demarcated, raised, bright-red erythema with tongue-like extensions and early systemic symptoms (fever/chills preceding or concurrent with skin findings). [1-2][5] It is distinguished from cellulitis by its more superficial involvement, brighter erythema, sharper borders, and more prominent early constitutional symptoms. [1][5][22]

Severity stratification per IDSA: [9]

• Mild: No systemic signs of infection → outpatient oral antibiotics
• Moderate: Systemic signs (fever, tachycardia, leukocytosis) → systemic antibiotics, consider observation/admission
• Severe: SIRS criteria, hemodynamic instability, immunocompromised, or concern for deeper infection → hospitalization, IV antibiotics, surgical consultation if necrotizing infection suspected

Complications: Abscess formation, bacteremia (<5%), lymphatic damage leading to chronic lymphedema, recurrence (8–20%/year), and rarely progression to necrotizing fasciitis. [8-9]

16. Treatment Plan

Initial stabilization

• IV fluid resuscitation if septic; hemodynamic support as needed.
• Elevation of the affected extremity to reduce edema. [9]

Antibiotic therapy

Adjunctive measures

• Treat the entry portal — antifungal therapy for tinea pedis (topical terbinafine or clotrimazole), wound care for ulcers. [6][9]
• Compression stockings and lymphedema management for venous insufficiency/edema. [14]
• Weight management counseling for obese patients. [4][6]
• Recurrence prophylaxis (≥2 episodes/year): Penicillin V 250 mg PO BID; duration is indefinite as recurrence resumes after discontinuation. [9][14]

The PATCH II trial demonstrated that penicillin prophylaxis significantly reduced recurrence during the treatment period (HR 0.51), but the benefit was lost after cessation of prophylaxis. [14][23]

17. Disposition

• Discharge (outpatient): No SIRS, hemodynamically stable, able to tolerate oral antibiotics, reliable follow-up, no concern for deeper infection. [9]
• Observation/admission:
  • SIRS criteria or systemic toxicity [9]
  • Failed outpatient therapy (no improvement at 48–72 hours)
  • Immunocompromised patients [9]
  • Concern for necrotizing fasciitis or abscess requiring drainage [9]
  • Inability to tolerate oral medications or poor adherence risk [9]
• Surgical consultation: Suspected necrotizing fasciitis, abscess requiring I&D, or rapidly progressive infection despite IV antibiotics. [10]

18. Follow Up / Return Precautions

• Follow-up: Reassess in 48–72 hours to confirm clinical improvement (reduction in erythema, pain, fever). Note: erythema may initially worsen slightly after starting antibiotics due to bacterial lysis releasing inflammatory mediators — this does not necessarily indicate treatment failure. [9]
• Return precautions — instruct patients to return immediately for:
  • Worsening redness, swelling, or pain despite antibiotics
  • New skin discoloration (purple/black), blistering, or skin breakdown
  • High fever, rigors, or feeling significantly worse
  • Numbness over the affected area
  • Red streaking spreading up the limb
• Patient counseling:
  • Complete the full antibiotic course
  • Keep the affected limb elevated as much as possible
  • Treat and prevent tinea pedis (keep feet dry, use antifungal powder)
  • Moisturize skin to prevent cracking
  • Manage edema with compression if applicable
• Expected recovery: Clinical improvement typically within 24–48 hours of appropriate antibiotics. Full resolution of erythema may take 1–2 weeks. Residual skin changes (hyperpigmentation, mild edema) may persist. [3][5]

References

1. Frequent Bacterial Skin and Soft Tissue Infections: Diagnostic Signs and Treatment. — Sunderkötter C, Becker K. Journal Der Deutschen Dermatologischen Gesellschaft = Journal of the German Society of Dermatology : JDDG. 2015.

2. Cellulitis: A Review. — Raff AB, Kroshinsky D. The Journal of the American Medical Association. 2016.

3. Analysis of Epidemiology, Clinical Features and Management of Erysipelas. — Krasagakis K, Valachis A, Maniatakis P, et al. International Journal of Dermatology. 2010.

4. Primary and Recurrent Erysipelas-Epidemiological Patterns in a Single-Centre Retrospective Analysis. — Matych M, Ciosek A, Miler K, et al. Journal of Clinical Medicine. 2025.

5. Constitutional Symptoms and Response to Penicillin G in Erysipelas and Cellulitis - A Monocentric, Retrospective, Explorative Study. — Schieffers H, Sunderkötter C. Journal Der Deutschen Dermatologischen Gesellschaft = Journal of the German Society of Dermatology : JDDG. 2026.

6. Risk Factors for Erysipelas of the Leg (Cellulitis): Case-Control Study. — Dupuy A, Benchikhi H, Roujeau JC, et al. BMJ. 1999.

7. Streptococcal Infections of Skin and Soft Tissues. — Bisno AL, Stevens DL. The New England Journal of Medicine. 1996.

8. Intracellular Streptococcal Uptake and Persistence: A Potential Cause of Erysipelas Recurrence. — Jendoubi F, Rohde M, Prinz JC. Frontiers in Medicine. 2019.

9. Practice Guidelines for the Diagnosis and Management of Skin and Soft Tissue Infections: 2014 Update by the Infectious Diseases Society of America. — Stevens DL, Bisno AL, Chambers HF, et al. Clinical Infectious Diseases : An Official Publication of the Infectious Diseases Society of America. 2014.

10. Necrotizing Soft Tissue Infections: A Review. — McDermott J, Kao LS, Keeley JA, et al. JAMA Surgery. 2024.

11. Erysipelas and Necrotizing Fasciitis. — Hammar H, Wanger L. The British Journal of Dermatology. 1977.

12. Assessment of Antibiotic Treatment of Cellulitis and Erysipelas: A Systematic Review and Meta-analysis. — Brindle R, Williams OM, Barton E, Featherstone P. JAMA Dermatology. 2019.

13. Appropriate Use of Short-Course Antibiotics in Common Infections: Best Practice Advice From the American College of Physicians. — Lee RA, Centor RM, Humphrey LL, et al. Annals of Internal Medicine. 2021.

14. Interventions for the Prevention of Recurrent Erysipelas and Cellulitis. — Dalal A, Eskin-Schwartz M, Mimouni D, et al. The Cochrane Database of Systematic Reviews. 2017.

15. Antibiotic Prophylaxis for Preventing Recurrent Cellulitis: A Systematic Review and Meta-Analysis. — Oh CC, Ko HC, Lee HY, et al. The Journal of Infection. 2014.

16. Risk Factors of Recurrent Erysipelas in Adult Chinese Patients: A Prospective Cohort Study. — Li A, Wang N, Ge L, Xin H, Li W. BMC Infectious Diseases. 2021.

17. Risk of Deep Vein Thrombosis in Patients With Cellulitis and Erysipelas: A Systematic Review and Meta-Analysis. — Gunderson CG, Chang JJ. Thrombosis Research. 2013.

18. Incidence of Deep Vein Thrombosis in Erysipelas or Cellulitis of the Lower Extremities. — Mortazavi M, Samiee MM, Spencer FA. International Journal of Dermatology. 2013.

19. Recurrent Erysipelas--Risk Factors and Clinical Presentation. — Inghammar M, Rasmussen M, Linder A. BMC Infectious Diseases. 2014.

20. Epidemiology and Comorbidity of Erysipelas in Primary Care. — Bartholomeeusen S, Vandenbroucke J, Truyers C, Buntinx F. Dermatology. 2007.

21. Clinical Mimics: An Emergency Medicine-Focused Review of Cellulitis Mimics. — Blumberg G, Long B, Koyfman A. The Journal of Emergency Medicine. 2017.

22. Diagnostic Value of Laboratory Parameters for the Discrimination Between Erysipelas and Limited Cellulitis. — Drerup C, Eveslage M, Sunderkoetter C, Ehrchen J. Journal Der Deutschen Dermatologischen Gesellschaft = Journal of the German Society of Dermatology : JDDG. 2020.

23. Penicillin to Prevent Recurrent Leg Cellulitis. — Thomas KS, Crook AM, Nunn AJ, et al. The New England Journal of Medicine. 2013.