Clinical: Cutaneous Reactions

Question 1

Pathogenesis of allergic contact dermatitis

Answer 1

Type IV hypersensitivity causing eczematous reaction in the skin to an allergen

Question 2

Presentation of allergic contact dermatitis

Answer 2

Acute: vesicles, bullae
Subacute: microvesicles, erythema, scale
Chronic: lichenification, scaling, erythema

Question 3

Unique pattern of allergic contact dermatitis caused by plants

Answer 3

Linear nature of vesicle distribution

Question 4

4 most common shampoo allergens that cause allergic contact dermatitis

Answer 4

Cocamidylpropyl Betaine
Fragrance
Formaldehyde Releasers
MCI (Miss Chinese International pageant)

Question 5

Diagnositc test for allergic contact dermatitis

Answer 5

Patch Test

Question 6

Treatment for allergic contact dermatitis

Answer 6

Short Term topical corticosteroids

Antihistamines

Question 7

Pathogenesis of Irritant Contact Dermatitis

Answer 7

Eczematous reaction secondary to exposure to a harsh product (alkali) or repeated exposure to a mild irritant (water)

Question 8

Treatment for Irritant Contact Dermatitis

Answer 8

Avoid the irritant

Question 9

Pathogenesis of Phytophotodermatitis

Answer 9

Reaction to furocoumarins in certain plants (limes). Reaction only occurs once the patient is exposed to UV light.
-erythema, edema, hyperpigmentation

Question 10

Most common scenario for Morbilliform Drug Eruption

Answer 10

Patient with mono put on ampicillin has a drug reaction. Systemic pruritis and erythema.

Question 11

Treatment for Morbilliform Drug Eruption

Answer 11

Topical steroids, systemic antihistamines

-remove offending medication

Question 12

Pathogenesis of Drug Hypersensitivity Syndrome

Answer 12

AKA Drug Rash with Eosinophilia and Systemic Symptoms (DRESS)

• drug causing eosinophilic reaction in the body creating a rash and chance of internal organ (liver) inflammation
• can be a life threatening condition

Question 13

How is DRESS different from Morbilliform eruption?

Answer 13

Morbilliform will have normal Liver Function Tests, no eosinophilia, lack of fever and lymphadenopathy

Question 14

Pathogenesis of Stevens-Johnson syndrome (SJS)

Answer 14

Hypersensitivity reaction to drugs (or infections) leading to dermoepidemal junction cell death causing the epidermis to separate from the dermis

Question 15

Treatment for Stevens-Johnson Syndrome

Answer 15

Corticosteroids early

Question 16

Pathogenesis of Toxic Epidermal Necrolysis (TEN)

Answer 16

Hypersensitivity reaction to drugs (or infections) leading to dermoepidemal junction cell death causing the epidermis to separate from the dermis

Question 17

How are SJS and TEN different?

Answer 17

They are the exact same thing. SJS involves only about 10% of the skin. If more than 30% of the skin is involved the name changes to TEN.

Question 18

What is a fixed drug eruption?

Answer 18

Annular, erythematous plaque that forms on the skin in the exact same spot every time a patient takes a certain medication.

Question 19

Culprit in any Urticaria

Answer 19

Mast cells

Question 20

Classification of Urticaria

Answer 20

Acute: occurring for less than 6 weeks
Chronic: occurring for more than 6 weeks, at least 2x a week
Episodic: occurring longer than 6 weeks but less than 2x a weeks

Question 21

Most common known cause of Acute Urticaria

Answer 21

Upper Respiratory Tract infection (usually strep)

Question 22

Treatment for Dermatographism

Answer 22

Antihistamines

Question 23

Cause of Cholinergic Urticaria

Answer 23

Any activity that raises core body temperature

also treat with antihistamines

Question 24

Most common cause of Solar Urticaria

Answer 24

UVA exposure

Question 25

Rash pattern and cause of Erythema Multiforme

Answer 25

Targetoid Lesion

Most commonly caused by HSV

Question 26

Rash pattern of Erythema Nodosum

Answer 26

Symmetric, tender, red nodules usually on anterior legs (type of septal panniculitis or SubQ fat inflammation)

Question 27

Most common cause of erythema nodosum in children

Answer 27

Strep infection

Question 28

Most common causes of erythema nodosum in adults

Answer 28

Infection
Drugs
Sarcoidosis
Autoimmune Diseases

Question 29

What is the “id” reaction

Answer 29

AKA Autosensitization Dermatitis

A widespread eczematous reaction occurring secondary to a severe primary dermatitis

Question 30

Most common cause of “id” reactions

Answer 30

Severe Stasis dermatitis

Question 31

Most common cause of Chronic Autoimmune Urticaria

Answer 31

Patients have IgG Abs to the Fc portion of IgE