Infectious Disorders

Question 1

What is impetigo? Cause? Population? Presentation?

Answer 1

Superficial bacterial skin infection most often due to S. aureus or S. pyogenes; Commonly affecting children; Erythematous macules that progress to pustules normally on the face. Rupture results in erosion and dry, crusted honey-colored serum

Question 2

What is cellulitis? Cause? Presentation? Risk factors? What can it progress to?

Answer 2

Deeper (dermal/subcutaneous) infection, usually due to S. aureus or S. pyogenes presenting as a red, tender, swollen rash with fever; Surgery, trauma, insect bite, Necrotizing fasciitis

Question 3

What is necrotizing fasciitis? Clinical presentation?

Answer 3

Necrosis of subcut. tissues due to infection with anaerobic “flesh-eating” bacteria; Crepitus due to CO2 production, Surgical emergency

Question 4

What is Staphylococcal Scalded Skin Syndrome? Cause?

Answer 4

Sloughing of skin with erythematous rash and fever leading to significant skin loss; S. aureus infection and exfoliative A and B toxins resulting in epidermolysis of stratum granulosum

Question 5

Distinguish between Staphylococcal Scalded Skin Syndrome and Toxic Epidermal Necrolysis?

Answer 5

Level of skin separation. Separation in TEN occurs at the dermal-epidermal junction

Question 6

What is verruca? Presentation? Infectious agent? Histological findings? Area of body commonly infected?

Answer 6

A wart; Flesh-colored papules with rough surface; Due to HPV infection of keratinocytes; Koilocytic change; Hands/feet most common

Question 7

What is Molluscum contagiosum? Infectious agent? Histo findings? Population affected?

Answer 7

Firm, pink umbilicated papules; Poxvirus; Keratinocytes show cytoplasmic inclusions; Children, sexually active adults and immunocompromised