Impetigo

Question 1

What is impetigo?

How does it present?

Who does it affect?

Answer 1

Impetigo is a highly contagious superficial bacterial skin infection (pyoderma) spread by direct contact.

Very common in children.

Inflamed, erythamatous pustules with a golden, crusted surface, most common around mouth and nose.

Question 2

What causes impetigo?

Answer 2

Staphylococcus aureus
*toxin producing strains of staph. aureus can cause blisters => bulbous impetigo

Streptococcus pyogens

Question 3

What predisposes to impetigo?

Answer 3

Atopic eczema

Scabies

Skin trauma i.e. chickenpox, insect bite, abrasion, burn, dermatitis, surgical wound

Question 4

What is the clinical presentation of impetigo?

Answer 4

Primary impetigo: affects exposed areas i.e. face and hands, trunk, perineum

=> Single or multiple, irregular bouts of irritable superficial plaques

=> Plaques extend as they heal, forming annular or arcuate lesions

=> Lymphadenopathy, mild fever and malaise may occur

1. Nonbullous impetigo:

=> starts as a pink macule - evolves into a vesicle or pustule and then into crusted erosions

=> untreated impetigo resolves within 2 to 4 weeks without scarring

2. Ecthyma:
   => starts as nonbullous impetigo but develops into a punched-out necrotic ulcer

=> heals slowly, leaving a scar

3. Bullous impetigo:
   => small vesicles evolves into flaccid transparent bullae

=> heals without scarring

Question 5

How is impetigo diagnosed?

Answer 5

Impetigo is diagnosed clinically but can be confirmed by bacterial swabs sent for microscopy (gram-positive cocci are observed), culture and sensitivity.

Bloods: neutrophil leucocytosis if impetigo widespread

5

Question 6

How is impetigo managed?

Answer 6

Topical fusidic acid

Mupirocin for MRSA cases

Oral antibiotics for 7 days i.e. flucloxacillin or erythromycin if patient has penicillin allergy => for widespread or bullous impetigo

Avoid school until lesions are dry or 48hrs after starting antibiotics