Contact dermatitis

Question 1

Lip lickers dermatitis ddx

Answer 1

ACD
perioral granulomatous dermatitis
contact dermatitis from mangos

Question 2

Diaper dermatitis clinical presentation

Answer 2

An irritant dermatitis that usually spares the folds

Need to r/o perianal psoriasis and perianal strep cellulitis

Question 3

Fiber glass dermatitis

Answer 3

An irritant dermatitis that presents as pruritic, patchy folliculitis or subacute dermatitis

Question 4

Etiology of allergic contact dermatitis

Answer 4

Type IV (delayed hypersensitivity) requiring interaction between allergen and cutaneous Langerhans cells-> T lymphocyte activation

Question 5

Etiology in nickel sensitization vs fragrance and rubber

Answer 5

Nickel involves Th1, Th17, and Th22 while fragrance and lesser so rubber involve Th2

Question 6

Once sensitized, how quick before exposure leads to dermatitis

Answer 6

classically between 8-12 hours

Question 7

ID reaction clinical presentation

Answer 7

acute, usually symmetric eruptions that are very pruritic and is preceded by flaring pre-existing dermatitis/tinea/infection

Question 8

Contraindications to Patch testing

Answer 8

NOT antihistamines (only affect Type I reactions)
Oral steroids within the previous 3 weeks and potent topical steroids within 1 week

Question 9

Patch testing timeline

Answer 9

Patches kept in place for 48 hours, then initial reading 20-60 min post their removal with second reasing 72-96 hours post their placement (to distinguish irritant from allergic reaction)

Question 10

Difference between allergic contact dermatitis and contact allery

Answer 10

Contact allergy represents a positive reaction with no clinical significant

Question 11

Rhus dermatitis: cause of the reaction

Answer 11

Delayed contact hypersensitivity to an oleoresin (urushiol) of which the active sensitizing ingredient is a pentadecylcatechol

Question 12

Recommendations for post Rhus exposure

Answer 12

wash thoroughly asap to remove the oil (remember the fluid of the vesicles is not contagious)

Question 13

Tx of mild Rhus dermatitis

Answer 13

calamine lotion (not benadryl cream/benzocaine)
Cool compresses
Topical steroids

Question 14

Tx of severe Rhus dermatitis

Answer 14

short term steroids at 1mg/kg/day tapered over 203 weeks (if dc too soon, can have rapid rebound)

Question 15

Nickel dermatitis: ear piercing advice

Answer 15

wear stainless steel or titanium earrings until hole is healed in 3 weeks

Question 16

Nickel free diet

Answer 16

Avoid canned foods, chocolate, cocoa, soy beans, cashews, almonds, oatmeal, legumes, and several fish and shellfish

Question 17

Shoe dermatitis

Answer 17

Classically presents on dorsal surface of the base of the big toe. Interdigital spaces are spared unlike in tinea

Question 18

Most common allergen behind shoe dermatitis

Answer 18

Rubber components

Question 19

Distribution of allergy to baby shampoo/wet wipes

Answer 19

face, perianal, and hands

Question 20

Distribution of allergy to nail polish

Answer 20

eyelids, cheeks, lips, chin, and neck rather than the nails themselves

Question 21

When to suspect Lanolin allergy

Answer 21

Children who tolerate vasoline but not Aquaphor/Eucerin

Question 22

Most common steroids to which patient have allergic contact dermatitis

Answer 22

Hydrocortisone topically and oral prednisone

Question 23

Which steroids are used to test for topical steroid allergy

Answer 23

Budesonide, hydrocortisone 17-butyrate, and tixocortol pivalate