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Round Rash

A 4 year old girl in day care was brought to the doctor because of several lesions on her arm. They were reddish and round, slightly raised and scaling. There were a few pinpoint pustules around the edge of the lesions. The girl had no other lesions except the ones on the arm and had no other symptoms.

Question 1 - Single Best Answer

What are three possible diagnoses that spring immediately to mind?

Chickenpox, Lyme disease, and impetigo
Rocky Mt. Spotted fever, impetigo and congenital syphilis
Impetigo, ringworm, and Lyme disease
Ringworm, Fifth disease, secondary syphilis

Question 2 - Single Best Answer

What is the causative agent of Lyme disease?

Treponema pallidum
Borrelia burgdorferi
Staphylococcus aureus
Tinea cruris

Question 3 - Single Best Answer

What is the causative agent of impetigo?

Staphylococcus aureus
Streptococcus pyogenes
Epidermophyton
It is a hypersensitivity reaction

Question 4 - Single Best Answer

What is the causative agent of ringworm?

Streptococcus pyogenes
Trichophyton
Tinea corporis
Enterobius vermicularis

Question 5 - Single Best Answer

What class of agents are Trichophyton, Microsporum, and Epidermophyton?

Bacteria
Viruses
Worms
Fungi

Question 6 - Single Best Answer

How would a case of ringworm be diagnosed?

Microscopic examination looking for tiny worms
Microscopic examination looking for hyphae
Growth of a swab on blood agar looking for hemolytic colonies
Look for serum antibodies to the fungus

Question 7 - Single Best Answer

To do a microscopic exam for fungi one should do which of the following first?

Gram stain
Treat the skin scraping with 10% KOH
Grow it on blood agar first
Grow it on SabouraudÕs agar first
Illuminate it with a WoodÕs lamp

A scraping of skin from the edge of the lesion on the childÕs arm was taken, treated with KOH, and examined under the microscope. Filamentous structures were seen. No flouresence with a WoodÕs lamp was seen.

Question 8 - Single Best Answer

This would lead you to diagnose

ringworm
impetigo
Lyme disease
None of the above

Question 9 - Single Best Answer

Can ringworm progress to a more serious systemic disease?

Yes, it can have serious sequelae, most often it infects the lungs being transported there hematogenously.
Only in immunocompromised patients
No, it is a superficial skin disease only

Question 10 - Single Best Answer

Do you know of a fungal disease that starts with a skin lesion and spreads, usually along the lymphatic glands that drain the primary site of inoculation?

Sporotrichosis
Tinea capitis
Histoplasmosis
Rocky Mountain Spotted Fever
Toxic Shock Syndrome

Question 11 - Single Best Answer

Which if the following is used to treat ringworm?

Penicillin
Metronidazole
Griseofulvin
Acyclovir

Question 12 - Single Best Answer

Fungi have cell walls that contain N-acetylglucosamine, so why doesnÕt penicillin work on fungi?

fungi are eukaryotes and penicillin only works on prokaryotes.
fungi have a cell membrane that contains sterols like ergosterol
fungi have a true nucleus
fungi contain mitochondria

The child was treated with topical miconazole and completely recovered.

Question 13 - Single Best Answer

What is the mechanism of action of miconazole?

it interacts with sterols in the cell membrane
it is deaminated to flourouracil and incorporated into RNA
it inhibits sterol biosynthesis
it inhibits microtubular function and acts as a mitotic poison

Question 14 - Single Best Answer

What is the mechanism of action of griseofulvin?

it interacts with sterols in the cell membrane
it is deaminated to flourouracil and incorporated into RNA
it inhibits sterol biosynthesis
it inhibits microtubular function and acts as a mitotic poison

Question 15 - Single Best Answer

How is ringworm acquired?

Other people
Animals
The environment; i.e., soil
All of the above

In summary, the child had a case of ringworm or tinea corporis. It was easily cured with a topical anti- fungal agent. Had it not been, she would have been treated with griseofulvin. She likely acquired it from another child in her day care center. Other names for fungal skin diseases are tinea capitis (scalp), tinea cruris (groin, also called jock itch), tinea pedis (feet, also called athleteÕs foot). By the way, do you know what disease killed Captain Hook? It was jock itch!


   

 Location: http://medinfo.ufl.edu/year2/mmid/a45aq.html
  Updated: October 6, 2005

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