Question 1

Which of the following best describes a 'bulla' as used in dermatology?

Accepted Answer

A large, fluid-filled lesion greater than 1 cm in diameter

Question 2

A patient presents with clusters of painful, pus-filled lesions around a hair follicle. Laboratory tests reveal a Gram-positive coccus that is coagulase positive. Which organism is most likely responsible?

Accepted Answer

Staphylococcus aureus

Question 3

Which of the following is a distinguishing feature of Staphylococcus aureus that contributes to its pathogenicity?

Accepted Answer

Production of coagulase enzyme

Question 4

A child develops honey-colored crusted lesions on the face. Which disease and organism are most likely involved?

Accepted Answer

Impetigo caused by Staphylococcus aureus

Question 5

Which of the following best differentiates between alpha, beta, and gamma hemolytic streptococci?

Accepted Answer

Alpha hemolysis is partial lysis with greenish discoloration, beta is complete lysis, gamma is no lysis

Question 6

A patient presents with rapidly spreading, painful erythema and tissue necrosis following a minor cut. The causative agent is a beta-hemolytic, Gram-positive coccus. What is the most likely diagnosis?

Accepted Answer

Necrotizing fasciitis caused by Streptococcus pyogenes

Question 7

Which of the following is a common characteristic of Pseudomonas aeruginosa skin infections?

Accepted Answer

They are associated with a fruity odor and blue-green pus

Question 8

Gas gangrene is most accurately described as:

Accepted Answer

A necrotizing infection caused by anaerobic, spore-forming bacteria producing gas in tissues

Question 9

Which of the following is NOT a recommended treatment option for gas gangrene?

Accepted Answer

Topical antifungal creams

Question 10

Which type of acne is characterized by deep, inflamed, pus-filled cysts that can result in scarring?

Accepted Answer

Nodular cystic acne

Question 11

A patient develops a vesicular rash that starts on the trunk and spreads to the face and limbs. The lesions are at different stages of development. Which organism is responsible?

Accepted Answer

Varicella-zoster virus

Question 12

Shingles is caused by reactivation of which virus?

Accepted Answer

Varicella-zoster virus

Question 13

Which of the following is a typical presentation of herpes labialis?

Accepted Answer

Vesicular lesions on the lips caused by human herpesvirus 1

Question 14

Which sign is unique to measles and helps distinguish it from other viral exanthems?

Accepted Answer

Koplik spots on the buccal mucosa

Question 15

Congenital rubella syndrome is a risk when rubella infection occurs during which period?

Accepted Answer

During the first trimester of pregnancy

Question 16

Which of the following statements about smallpox is correct?

Accepted Answer

It is caused by a DNA virus and presents with synchronous pustular lesions

Question 17

Which organism is most commonly associated with the formation of warts?

Accepted Answer

Human papillomavirus

Question 18

Dermatophytes are best defined as:

Accepted Answer

Fungi that infect keratinized tissues such as skin, hair, and nails

Question 19

A wrestler develops vesicular lesions on the trunk after close contact with another wrestler. Which condition is most likely?

Accepted Answer

Herpes gladiatorum

Question 20

Which of the following tinea infections is commonly known as 'athlete's foot'?

Accepted Answer

Tinea pedis

Microbial Diseases of the Skin: Pathogenesis, Presentation, and Key Organisms

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