Erysipelas
BASICS
DESCRIPTION
- Acute superficial bacterial skin infection with well-demarcated erythema and lymphatic involvement.
- Most commonly caused by Group A Streptococcus (Streptococcus pyogenes).
- Can be acute or chronic recurrent.
- Nonpurulent infection.
- Affects skin and exocrine system.
EPIDEMIOLOGY
- Predominantly affects infants, children, adults >45 years; greatest incidence in elderly (>75 years).
- No gender or racial predilection.
- Incidence: ~24 per 1,000 persons/year; increasing since 1980s.
- Prevalence unknown.
ETIOLOGY AND PATHOPHYSIOLOGY
- Caused by Group A β-hemolytic streptococci (mostly S. pyogenes), sometimes groups C/G.
- Rarely group B streptococci or Staphylococcus aureus.
- Infection triggers inflammatory cascade involving:
- Contact system activation → proinflammatory cytokines, proteinases, bradykinin release.
- M protein interaction with neutrophils → heparin-binding protein secretion → vascular leakage.
- Result: fever, pain, erythema, edema.
RISK FACTORS
- Disruption of skin barrier (incisions, bites, trauma, dermatophytes, IV drug use).
- Chronic illnesses: diabetes, malnutrition, nephrotic syndrome, heart failure.
- Immunocompromise (e.g., HIV).
- Skin fissures (nose, ears).
- Toe-web intertrigo, lymphedema, leg ulcers, venous insufficiency.
- Alcohol abuse, morbid obesity.
- Recent streptococcal pharyngitis, varicella infection.
GENERAL PREVENTION
- Good skin hygiene.
- Manage predisposing conditions (e.g., tinea pedis, stasis dermatitis).
- Avoid shaving face within 5 days of facial erysipelas (risk of recurrence).
- Compression stockings for lower extremity edema.
- Consider prophylactic penicillin in recurrent cases (>2 episodes/year).
PEDIATRIC CONSIDERATIONS
- Group B Streptococcus may cause erysipelas in neonates and infants.
DIAGNOSIS
HISTORY
- Prodromal symptoms: moderate to high fever, chills, headache, malaise, anorexia, vomiting, arthralgia.
- Importance of differentiating from MRSA (which has indurated centers and abscess formation).
PHYSICAL EXAM
- Fever and tachycardia common; hypotension possible.
- Acute onset of painful, well-demarcated erythematous plaque with peau d’orange appearance.
- Milian ear sign (ear involvement indicates erysipelas vs cellulitis).
- Possible vesicles, bullae, desquamation.
- Lymphangitis and regional lymphadenopathy.
- Commonly unilateral; lower extremities (70-80%) > face (5-20%).
- Chronic form may recur at previous site.
- Steroid use may mask signs.
- In elderly, facial butterfly pattern and lymphangitic streaking common.
DIFFERENTIAL DIAGNOSIS
- Cellulitis (less distinct margins, no ear involvement).
- Necrotizing fasciitis (severe pain, systemic illness).
- Skin abscess.
- Deep vein thrombosis.
- Acute gout, insect bites, dermatophytes.
- Impetigo, ecthyma.
- Herpes zoster, erythema annulare centrifugum.
- Contact dermatitis, giant cell urticaria.
- Angioneurotic edema, scarlet fever, toxic shock syndrome.
- Lupus, polychondritis.
- Other bacterial infections from animal bites, water exposure.
DIAGNOSTIC TESTS
- Reserved for severe or immunocompromised patients or treatment failures.
- Leukocytosis, elevated ESR and CRP common.
- Blood cultures rarely positive (<5%).
- Cultures from exudate or noninvolved sites may isolate streptococci.
- Biopsy not routine: shows dermal/epidermal edema, vasodilation, neutrophilic infiltrates, M protein effects.
TREATMENT
GENERAL MEASURES
- Symptomatic treatment: fever, myalgia, hydration, cold compresses, limb elevation.
- Manage underlying risk factors.
MEDICATION
First Line - Adults
- Extremities, nondiabetic:
- Penicillin G 1-2 million units IV q6h or cefazolin 1 g IV q8h.
- Penicillin allergic: Vancomycin 15 mg/kg IV q12h.
- Switch to oral TMP-SMX or clindamycin when afebrile to complete 10 days.
Early mild disease (diabetics)
- TMP-SMX DS 1-2 tabs PO BID plus penicillin VK 500 mg or cephalexin 500 mg PO QID.
Severe disease
- Meropenem, ertapenem, linezolid, vancomycin, or daptomycin IV as needed.
Facial erysipelas
- Vancomycin 15 mg/kg IV q8-12h (target trough 15-20).
- Alternatives: daptomycin or linezolid IV.
CHILDREN
- Penicillin G (dose varies by age and weight).
- Cefazolin also used.
- No reported Group A streptococcal resistance to β-lactams.
RECURRENT CASES
- Prophylactic Penicillin G benzathine 1.2 million U IM q4wk or penicillin VK 500 mg BID or azithromycin 250 mg QD.
ADDITIONAL THERAPIES
- Topical 1% hydrocortisone trial if worsening symptoms after antibiotics.
ADMISSION CRITERIA
- Systemic toxicity.
- High-risk patients (elderly, lymphedema, postsplenectomy, diabetes).
- Failed outpatient therapy.
- IV therapy if unable to tolerate PO.
ONGOING CARE
FOLLOW-UP
- Bed rest and limb elevation during acute phase; resume activity as tolerated.
PROGNOSIS
- Usually full recovery with treatment.
- Skin erythema may worsen initially after antibiotics.
- Most improve within 24-48 hours.
- Mortality <1% with appropriate therapy.
- Bullae indicate longer course and possible S. aureus coinfection.
COMPLICATIONS
- Recurrent infection.
- Abscess formation (suggests staphylococcal involvement).
- Necrotizing fasciitis.
- Lymphedema (risk factor for recurrence).
- Bacteremia/sepsis.
- Pneumonia, meningitis due to sepsis.
- Embolism, gangrene.
- Septic bursitis, arthritis, tendinitis, osteitis.
REFERENCES
- Jendoubi F, Rohde M, Prinz JC. Intracellular streptococcal uptake and persistence: a potential cause of erysipelas recurrence. Front Med. 2019;6:6.
- Breen JO. Skin and soft tissue infections in immunocompetent patients. Am Fam Physician. 2010;81(7):893-899.
- Inghammar M, Rasmussen M, Linder A. Recurrent erysipelas—risk factors and clinical presentation. BMC Infect Dis. 2014;14:270.
CODES
CLINICAL PEARLS
- Athlete’s foot is the most common portal of entry.
- Erysipelas distinguished from cellulitis by sharp, shiny, fiery-red raised borders.
- Most cases now affect the legs rather than the face.
- In recurrent cases, evaluate for other sources such as tonsils, sinuses, or intertrigo.