Dermatology

Question 1

Pityriasis rosea

Answer 1

Acute exanthem, commonly affects children and young adults.
HHV6 and HHV7
Initial herald patch, followed by the development of a diffuse papulosquamous rash.

Question 2

Alkali burns vs acid

Answer 2

Alkali burns causes liquefactive necrosis of involved tissues. Acid burns cause coagulation necrosis, which is slower in manifestation.

Question 3

First-line treatment of acne rosacea.

Answer 3

Topical metronidazole

Question 4

Erythropoeitic protoporphyria

Answer 4

Deficiency of the ferrochelatase enzyme, the final enzyme in the heme biosynthesis pathway.
Accumulation of protoporphyrin substrate.
Acute cutaneous photosensitivity as well as hepatobiliary disease.
The inheritance is termed “pseudodominant”, as both autosomal recessive and dominant forms have been identified.
Excruciating pain, redness, and swelling of the skin after short-term sun exposure. Blisters, erosions, and scarring are less common.

Oral beta carotene may reduce photosensitivity in some patients.

Question 5

The diagnosis of vitiligo can be confirmed through?

Answer 5

Visualization of lesions under a Wood’s lamp, as hypopigmentation will fluoresces bright blue-white) due to accumulated biopterins

Question 6

Porphyria cutanea tarda histologically

Answer 6

‘caterpillar bodies’ - linear, eosinophilic, periodic acid-Schiff–positive globules - found in the blisters and skin lesions