Impetigo

Question 1

Define impetigo.

Answer 1

Impetigo is a superficial bacterial skin infection usually caused by either Staphylcoccus aureus or Streptococcus pyogenes.

Question 2

What are the risk factors for impetigo?

Answer 2

• Children
• Skin conditions: atopic dermatitis, contact dermatitis, scabies, chickenpox
• Skin trauma: lacerations, insect bites, thermal burns, abrasions
• Immunosuppression
• Warm, humid climate
• Poor hygiene
• Crowded environments

Question 3

Where on the body does impetigo usually occur?

Answer 3

Face, flexures and limbs not covered by clothing

Question 4

What are the two types of impetigo?

Answer 4

Bullous - typically staph as blistering is staph toxin mediated
Non-bullous - staph+/- strep; fever with regional lymphadenopathy, severe

NB: if a previous skin condition is infected by staph/strep then this is called impetiginisation

Question 5

What organisms cause impetigo?

Answer 5

Staphylococcus aureus
Streptococcus pyogenes (less common)

Question 6

How does impetigo spread?

Answer 6

Direct contact with discharges from scabs of an infected person
Bacteria will invade through minor abrasions and then spread to other sites by scratching
Mainly spread by hands but also toys, clothing, equipment and environment

Question 7

What is the incubation period of impetigo?

Answer 7

4-10 days

Question 8

How do you diagnose impetigo?

Answer 8

**Usually clinical diagnosis **

Other:

Swabs - may be taken for MC&S if recurrent lesions or worry about MRSA
Nasal swabs- n recurrent infection as they can identify staphylococcal nasal carriage which requires specific management.

Question 9

What is the management of impetigo?

Answer 9

1st line:

• Hydrogen peroxide 1% cream - if patient is well overall; aimed to reduce antibiotic resistance
• OR Topical fusidic acid
• AND School exclusion for 48hrs of antibiotics or until all lesions crusted and healed

Other:

• Topical mupirocin - if fucidic acid resistance; also used for MRSA which is resistant to fuscidic acid
• Oral flucloxacilin (pen allergic: erythromycin) - if extensive disease

Question 10

What is shown ?

Answer 10

Impetigo

Question 11

Describe this rash.

Answer 11

Honey coloured crusted erosions around the mouth

Question 12

What are the complications of impetigo?

Answer 12

Staphylococcal scalded skin syndrome
Post-streptococcal acute glomerulonephritis (18-21days)
Postinflammatory pigmentation
Scarlet fever
Streptococcal toxic shock syndrome

Question 13

What is the prognosis with impetigo?

Answer 13

Usually heal without scarring