impetigo

Question 1

What is impetigo?

Answer 1

Impetigo is a common, superficial, highly contagious bacterial skin infection characterized by pustules and honey-colored crusted erosions.

Question 2

Which layers of the skin does impetigo affect?

Answer 2

Impetigo affects the superficial layers of the epidermis.

Question 3

What are the common pathogens that cause impetigo?

Answer 3

The common pathogens are Staphylococcus aureus and Streptococcus pyogenes (Group A beta-hemolytic streptococci).

Question 4

What are the two types of impetigo?

Answer 4

Non-bullous (school sores) and bullous impetigo.

Question 5

What is ecthyma?

Answer 5

Ecthyma is a deep form of impetigo that causes deeper erosions of the skin into the dermis.

Question 6

What is impetiginisation?

Answer 6

Impetiginisation refers to the secondary infection of wounds or other skin lesions with the same pathogens that cause impetigo.

Question 7

Who is most commonly affected by impetigo?

Answer 7

Impetigo is most common in young children but can occur at any age.

Question 8

What skin conditions can predispose someone to impetigo?

Answer 8

Atopic dermatitis, contact dermatitis, scabies, and chickenpox.

Question 9

What bacteria can cause non-bullous impetigo?

Answer 9

Non-bullous impetigo can be caused by Staphylococcus aureus, Streptococcus pyogenes, or both bacteria together.

Question 10

How does non-bullous impetigo typically occur?

Answer 10

It occurs when a disruption in skin integrity allows bacteria to invade through the interrupted surface.

Question 11

Which bacteria causes bullous impetigo, and what toxins does it produce?

Answer 11

Bullous impetigo is caused by Staphylococcus aureus, which produces exfoliative toxins (exfoliatins A and B).

Question 12

What do exfoliative toxins target in bullous impetigo?

Answer 12

They target intracellular adhesion molecules (desmoglein-1) in the epidermal granular layer.

Question 13

Where is non-bullous impetigo most commonly found?

Answer 13

Non-bullous impetigo is most commonly found on the face or extremities, but it can occur on any part of the body.

Question 14

How does bullous impetigo present?

Answer 14

It presents as quickly appearing superficial, small or large thin-roofed bullae that tend to rupture and ooze yellow fluid, leaving a scaly rim (collarette).

Question 15

How does non-bullous impetigo initially present?

Answer 15

It begins with a single erythematous macule that evolves into a pustule or vesicle.

Question 16

What are “kissing lesions” in non-bullous impetigo?

Answer 16

“Kissing lesions” occur where two skin surfaces are in contact and lesions spread through autoinoculation.

Question 17

Where is bullous impetigo usually found?

Answer 17

Bullous impetigo is usually found on the face, trunk, extremities, buttocks, and perineal regions.

Question 18

What is scarlet fever, and how is it related to impetigo?

Answer 18

Scarlet fever is an illness caused by toxins from Streptococcus pyogenes, which can complicate impetigo.

Question 19

What topical treatments can be used for impetigo?

Answer 19

Dress or bathe affected areas with potassium permanganate, gentian violet (GV) paint, betadine solution, or saline, or wash with betadine shampoo.

Question 20

How can the spread of impetigo to others be prevented?

Answer 20

Do not share towels or ointments, and change clothes, towels, and sheets frequently.

Question 21

What should be avoided in the topical care of impetigo, and what should be used instead?

Answer 21

Avoid using Vaseline; use aqueous cream instead.

Question 22

What oral antibiotic is recommended for severe cases of impetigo in adults?

Answer 22

Cloxacillin 250-500 mg four times daily for 7-10 days

Question 23

What is the recommended dosage of cloxacillin for children with severe impetigo?

Answer 23

50-100 mg/kg/24 hours, divided into four doses for 7-10 days.

Question 24

What is an alternative antibiotic for severe impetigo, and what is the adult dosage?

Answer 24

Erythromycin 250-500 mg four times daily for 7-10 days.

Question 25

What is the recommended dosage of erythromycin for children with severe impetigo?

Answer 25

25-50 mg/kg/24 hours, divided into four doses for 7-10 days