Honey Crusts to Butterfly Rash: Impetigo vs Erysipelas vs Cellulitis in Kids

 

Understanding Superficial Bacterial Skin Infections in Children: A Practical Guide for Medical Students & Young Doctors  -

(With Focus on Impetigo, Erysipelas, and Cellulitis)

### Introduction  -

Among the most common reasons parents rush to the pediatrician or dermatologist is a child with “oozing sores” on the face, arms, or legs. In dermatology and pediatrics, the vast majority of these cases fall under superficial pyodermas (bacterial skin infections) caused mainly by Streptococcus pyogenes (Group A beta-hemolytic streptococcus) and Staphylococcus aureus. The three classic entities every student must master are:

1. Impetigo (non-bullous & bullous)  

2. Erysipelas  

3. Cellulitis  

Although they are caused by almost the same bacteria, the depth of skin involvement decides the clinical picture, complications, and slight differences in management.

### 1. Impetigo – The Classic “Honey-Crusted” Infection  

Impetigo is the most superficial bacterial infection of the skin.

#### Key Clinical Features

- Most common in children 2–5 years of age  

- Starts as tiny vesicles or pustules that rupture quickly  

- Forms characteristic golden-yellow or “honey-coloured” crusts  

- Favourite sites: face (around nose & mouth), limbs, scalp  

- Mild itching or burning; rarely painful  

- Highly contagious – spreads by autoinoculation (same child) and direct contact (schools, siblings)

#### Two Types You Must Remember

- Non-bullous impetigo (90% of cases) → caused by Streptococcus pyogenes or Staphylococcus aureus → honey crusts  

- Bullous impetigo → almost always caused by exfoliative toxin-producing Staphylococcus aureus → flaccid, large bullae that rupture leaving superficial varnish-like crust

#### Depth of Involvement

Only the epidermis (stratum corneum & granular layer) is affected. The dermis is completely spared. That is why you see the classic “stuck-on” crust that can be easily scraped off.

#### Complications (Rare but Important)

- Post-streptococcal glomerulonephritis (PSGN) – can occur 2–3 weeks later (remember: impetigo-related PSGN is NOT prevented by antibiotics, but antibiotics reduce spread)  

- Very rarely → rheumatic fever (extremely uncommon with skin infections)

#### Treatment – Keep It Simple!

Mild, localised disease (few lesions)  

→ Topical antibiotics  

- Mupirocin 2% ointment (Bactroban) – 3 times daily × 5–7 days  

- Fusidic acid cream (Fucidin) – equally effective  

Extensive or multiple lesions / facial involvement / outbreaks in school  

→ Oral antibiotics (7–10 days)  

- First-line: Cephalexin or Amoxicillin-Clavulanate (first-generation cephalosporin or penicillinase-resistant penicillin)  

- Penicillin allergy (non-anaphylactic): Cefadroxil or Cefalexin  

- True anaphylactic penicillin allergy: Macrolides – Azithromycin (3–5 day course) or Clarithromycin  

- If community-acquired MRSA is suspected: Clindamycin or Doxycycline (only >8 yrs)

### 2. Erysipelas – “St. Anthony’s Fire”  

When the infection goes a little deeper and involves the upper dermis + dermal lymphatics, we call it erysipelas.

#### Classic Presentation

- Bright red, fiery-red, indurated, sharply demarcated plaque  

- “Butterfly” involvement of face is classic in children  

- Painful, warm, tender  

- Prominent lymphatic involvement → regional lymphadenopathy, lymphangitic streaking  

- Often preceded by fever, chills, malaise (more systemic symptoms than impetigo)

#### Depth

Epidermis + upper dermis + lymphatic vessels

#### Treatment  

Same bacteria → same antibiotics, but almost always oral or IV (because of systemic symptoms)  

- First-line: Penicillin V or Amoxicillin (oral)  

- Severe or facial: IV Penicillin G or Ceftriaxone  

- Penicillin allergy: Clindamycin or Vancomycin (if MRSA suspected)

### 3. Cellulitis – When the Infection Goes Even Deeper  

Cellulitis involves the deep dermis + subcutaneous fat.

#### Clinical Picture

- Poorly defined, dusky red, warm, swollen area  

- No sharp border (compare with erysipelas)  

- Marked tenderness  

- Fever, tachycardia, hypotension possible  

- May rapidly spread → life-threatening if not treated early

#### Depth

Deep dermis + subcutaneous tissue → can spread along fascial planes and enter bloodstream → sepsis, necrotizing fasciitis (rare but feared)

#### Special Points in Management

- Mark the border with a marker pen at presentation – helps monitor progression/regression  

- Blood cultures if systemic signs  

- Imaging (ultrasound/MRI) if abscess or necrotizing fasciitis suspected  

- Most cases still respond to high-dose IV antibiotics

#### Antibiotic Choices

Empiric therapy (covers both Streptococcus & Staphylococcus including MRSA in high-risk areas)  

- IV Ceftriaxone 1–2 g daily OR  

- IV Cefazolin + Vancomycin (if MRSA prevalent) OR  

- Clindamycin + Penicillin G (good streptococcal coverage)  

Switch to oral after 48–72 h of clinical improvement.

### Quick Comparison Table

| Feature | Impetigo | Erysipelas | Cellulitis |

|----------------------|---------------------------|-----------------------------|--------------------------------|

| Depth | Epidermis only | Upper dermis + lymphatics | Deep dermis + subcutis |

| Border | Irregular, crusted | Sharp, raised | Poorly defined |

| Colour of crust/exudate | Honey/golden | Bright red, no crust | Dusky red, no crust |

| Pain | Mild | Moderate–severe | Severe |

| Systemic symptoms | Rare | Common | Very common |

| Lymphadenopathy | Occasional | Prominent | Variable |

| Most common site | Face, extremities | Face, lower legs | Lower legs, face |

| Life-threatening | Topical ± oral | Oral or IV | Usually IV initially |

### Prevention & Public Health Tips

- Good hand hygiene in schools  

- Avoid sharing towels, clothes  

- Early treatment of minor wounds/abrasions  

- Nasal mupirocin in recurrent cases (decolonisation of Staphylococcus carrier state)

### Take-Home Message for Exams & Clinics

1. Honey-coloured crust → think Impetigo first  

2. Butterfly facial fiery red plaque with sharp border → Erysipelas  

3. Poorly defined tender warm swelling → Cellulitis  

4. Depth of invasion decides severity and route of antibiotic  

5. Group A Streptococcus is still the king in most pediatric superficial pyodermas worldwide.

Master these three, and you will confidently handle 95% of day-to-day pediatric bacterial skin infections!