Dermatology

Question 1

What is Actinic Keratosis?

Answer 1

Erythamous papules with central scaling with a sandpaper texture. Premalignant lesion caused by sun exposure. Seen on genetically predisposed 40 to 60 yo.

Question 2

What is CREST syndrome?

Answer 2

A type of scleroderma limited to the hands and face. Assc w/ anti-Centromere antibodies.
C = Calcinosis
R = Raynaud
E = Esophageal dysmotility (fibrous esophagus)
S = Sclerodactyly (curled immotile fingers)
T = Telangiectasia

Question 3

What skin condition is associated with celiac disease?

Answer 3

Dermatitis Herpetiformis. Cross reactivity of anti-gluten IgA/IgG with reticulin. Papulovesiclar rash with linear excoriations near the elbow.

Question 4

What characterizes Linchen Planus?

Answer 4

The 5 Ps:
Polygonal
Planar
Pruritic
Purple
Papules &
Plaques
Associated with hepatitis C.

Question 5

What is Isotretinoin?

What is its most important side effect?

Answer 5

A Vit A derivative used to treat severe acne. First topically then orally. When given orally it can be a powerful teratogen so patients must use two methods of BC and take pregnancy tests.

Question 6

What type of hypersensitivity is contact dermatitis?

Answer 6

Type IV. It involves mostly T lymphocytes of either CD8+ or CD4+.

Question 7

Which drugs have been known to cause Steven-Johnson syndrome?

Answer 7

Anti-epilptics. (Ethosuximide, Cabamezapine, Lamotrigine, Phenytoin, Phenobarbital)
Allopurinol
Sulfa drugs
Penicillin

Question 8

What are the differences between Pemphigus Vulgaris and Bullous Pemphigoid?

Answer 8

PV has anti-desmosome IgG and it has a positive Nikolsky sign. BP has anti-HEMIdesmosome IgG and it has a negative Nikolsky sign. Nikolsky sign is when the epidermis can be separated with a gentle stroke.

Question 9

What type of DNA damage is caused by UV light? How is it fixed?

Answer 9

Thymine dimers on adjacent Thymine residues of the same strand. Either Photolyase reverses this damage or UV-endonuclease removes part of the strand.