Contact dermatitis

Question 1

Irritant contact dermatitis

Answer 1

80% of contact dermatitis. It can be due to infrequent exposure to strong irritants or frequent exposure to milder irritants. Common exposures include frequent hand washing, hand sanitizers hand sopas, heavily fragrant skin products.

Question 2

Allergic contact dermatitis

Answer 2

20% of contact dermatitis. Previous sensitization is required. Once sensitization occurs minimal exposure can provoke a severe reaction.
This is a delayed reaction without risk for anaphylaxis (different from food allergies)

Question 3

Most common allergens for patch testing, exception

Answer 3

Nickel (by far most common), fragrances, balsam of Peru, neomycin, bacitracin.
The exception is the eyelid: gold
Quaternium 14 is a commonly use preservative used in fragances

Question 4

Nickel avoidance diet

Answer 4

Chocolate (big one), mussels, many nuts

Question 5

What test shows release of nickel from jewerly?

Answer 5

Dimethylglioxime test (not looking for content but for release of nickel)

Question 6

Preservatives as cause of contact dermatitis

Answer 6

Parabens common preservative, methhylsothiazoline (more common now, on medications, paints, cosmetic products), lanolin (coomon in cosmetic products)

Question 7

Preservatives as cause of contact dermatitis

Answer 7

Parabens common preservative, methylsothiazoline (more common now, on medications, paints, cosmetic products), lanolin (common in cosmetic products)

Question 8

Regional prediction of contact dermatitis

Answer 8

Eyelids: nail polish and cosmetics applied to that area
Perioral dermatitis and cheilitis” flavoring agents in dentifrice and gum
Under the ears and neck: perfume dermatitis
Earlobe: nickel dermatitis
Clear area under the chin and V shape in the chest: photocontact dermatitis
Axilla: deodorant & clothing dye
Arms: jewelry
Hands: innumerable sources
Lower extremities: Elastic stocking
Feet: Shoe dermatitis

Question 9

Occlusive, emollients and humectants

Answer 9

Occlusives block transepidermal water loss, but they are messy comedogenic and cosmetically unnaceptable: petrolatum and zinc oxide
Humectants: attract water to stratum corneum, but they can cause irritation: lactic acid, urea (Ex: ammonium lactate)
Emollients: they smooth the skin but may not be always effective: fatty acids, squalene (ex: Aveena)
Replacement of stratum corneum like ceramides, unproven

Question 10

Occlusive, emollients and humectants

Answer 10

Occlusives block transepidermal water loss, but they are messy comedogenic and cosmetically unnaceptable: petrolatum and zinc oxide
Humectants: attract water to stratum corneum, but they can cause irritation: lactic acid, urea (Ex: ammonium lactate)
Emollients: they smooth the skin but may not be always effective: fatty acids, squalene (ex: Aveena)
Replacement of stratum corneum like ceramides, unproven