Cellulitis and erysipelas are bacterial skin infections affecting the dermis and subcutaneous tissues. They lead to redness, swelling, warmth, and tenderness of the affected area. While cellulitis spreads deeply into the subcutaneous tissue, erysipelas is a more superficial infection affecting the upper dermis and lymphatics.

Incidence

More common in adults, diabetics, and immunocompromised individuals.
Cellulitis occurs more frequently in the lower limbs, while erysipelas affects the face and legs.
Higher incidence in people with venous insufficiency, lymphedema, and skin ulcers.

Definition

Cellulitis: A deep bacterial infection involving the dermis and subcutaneous tissue, causing diffuse swelling and pain.
Erysipelas: A superficial bacterial infection of the upper dermis and lymphatic vessels, presenting with bright red, raised, well-defined borders.

Etiology (Causes)

1. Causative Organisms

Streptococcus pyogenes (Group A Strep) – Most common cause of erysipelas.
Staphylococcus aureus – Common in cellulitis, especially in diabetic foot infections.
Methicillin-Resistant Staphylococcus Aureus (MRSA) – Increasingly seen in recurrent cellulitis cases.

2. Predisposing Factors

Skin Trauma – Cuts, insect bites, burns, surgery.
Diabetes Mellitus – Poor circulation and immune dysfunction.
Venous Insufficiency – Poor blood flow leads to recurrent infections.
Lymphedema – Stagnant lymph fluid promotes bacterial growth.
Obesity – Increases risk of leg cellulitis.
Fungal Infections – Tinea pedis (Athlete’s foot) can lead to lower limb cellulitis.

Pathogenesis of Cellulitis & Erysipelas (Mnemonic: I-SEE)

I – Injury or break in the skin (cut, wound, ulcer).
S – Strep/Staph bacteria invade the deeper skin layers.
E – Enzymes (hyaluronidase, streptokinase) help bacteria spread.
E – Edema, redness, and pus formation occur due to inflammation.

Clinical Features (Mnemonic: RED-SWELL)

Cellulitis

R – Red, warm, swollen skin.
E – Edema and pain in the affected limb.
D – Diffuse spread without clear borders.
S – Systemic symptoms (fever, chills).
W – Worsening over days if untreated.
E – Erythema (redness) with possible abscess formation.
L – Lymphangitis (red streaks along lymph vessels).
L – Late-stage complications (necrotizing fasciitis, sepsis).

Erysipelas

Bright red, raised rash with well-defined borders.
Painful swelling, mostly on the face or legs.
High fever, chills, and malaise.
Peau d’orange appearance (skin looks like orange peel).
Rapid spread within hours to days.

Complications

Abscess formation.
Sepsis – Bacterial spread into the bloodstream.
Necrotizing fasciitis – Rapidly spreading, life-threatening soft tissue infection.
Lymphangitis and recurrent infections leading to chronic lymphedema.

Laboratory Investigations

Complete Blood Count (CBC) – Shows leukocytosis (↑ WBC count).
C-Reactive Protein (CRP) & ESR – Elevated in severe infection.
Blood Cultures – May detect bacteremia in severe cases.
Wound Swab Culture – Identifies causative bacteria.
Doppler Ultrasound – Done to rule out deep vein thrombosis (DVT) in leg cellulitis.

Management of Cellulitis & Erysipelas

General Measures (Mnemonic: CLEAN)

C – Clean the wound with antiseptic solutions.
L – Leg elevation to reduce swelling.
E – Encourage hydration and proper skin hygiene.
A – Avoid scratching or irritating the affected area.
N – Nutrition support (high protein, vitamins).

Allopathic Treatment (Mnemonic: FAST)

F – Flucloxacillin, Cephalexin (Antibiotics of choice for Strep/Staph).
A – Analgesics (NSAIDs, Paracetamol for pain relief).
S – Supportive care (elevation, hydration, wound care).
T – Tetanus prophylaxis (if wound-related cellulitis).

Severe Cases (Requiring Hospitalization)

IV antibiotics (Ceftriaxone, Vancomycin for MRSA).
Surgical drainage if an abscess is present.

Surgical Treatment

Incision & Drainage (I&D) for abscess formation.
Debridement in cases of necrotizing fasciitis.

Homeopathic Treatment

1. Belladonna

Bright red, hot, swollen skin.
Throbbing pain with burning sensation.
Fever with dry, hot skin.
Sensitive to touch, worse at night.
Rapid onset of symptoms.

2. Apis Mellifica

Swelling with stinging, burning pain.
Skin is shiny, red, and edematous.
Better with cold applications.
Worse from heat, touch, and pressure.
Useful in cellulitis with rapid swelling and itching.

3. Hepar Sulphuris

Suppurative cellulitis with pus formation.
Extremely sensitive skin, painful to touch.
Pain worsens in cold air, better with warmth.
Foul-smelling discharge if an abscess forms.
Helps promote pus drainage.

4. Silicea

Chronic or slow-healing cellulitis.
Pus formation with delayed wound healing.
Extremely weak immunity, prone to infections.
Useful in recurrent skin infections and boils.
Cold hands and feet, poor circulation.

5. Lachesis

Dark purple, swollen skin in severe cellulitis.
Septicemia and blood poisoning symptoms.
Pain worsens after sleep, extreme sensitivity to touch.
Used in cellulitis with necrotic changes.
Red streaks along lymphatics, indicative of spreading infection.

Mnemonic for Homeopathic Treatment (BASH-L)

B – Belladonna (Acute red, hot swelling).
A – Apis Mellifica (Burning, edematous swelling).
S – Silicea (Chronic, slow-healing cellulitis).
H – Hepar Sulph (Suppurating, abscess formation).
L – Lachesis (Septic, purplish cellulitis).

Cellulitis vs. Erysipelas: Key Differences, Symptoms & Homeopathic Cure