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#2 Derm > 22 - Atopic and Contact Dermatitis > Flashcards

22 - Atopic and Contact Dermatitis Flashcards

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Dermatology Board Prep flashcards
1
Q

Eczematous dermatitis

A
  • An inflammatory response of the skin to many different external and internal stimulants
  • Cause usually unknown
  • Diagnosis often difficult
  • Many different subtypes
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2
Q

Types of eczematous dermatitis

A
  • Acute
  • Subacute
  • Chronic
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3
Q

Acute eczematous dermatitis

A

o Vesicles, blisters, or bullae

o Erythema and pruritis

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4
Q

Subacute eczematous dermatitis

A

o Erythema, scaling, fissuring

o Parched or scalded appearance

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5
Q

Chronic eczematous dermatitis

A

o Lichenification, fissuring and accentuated skin lines

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6
Q

Asteatotic dermatitis

A

Characterized by
o Dry scaling
o Fine superficial cracking

Develops due to decreased skin surface lipids
o Dry winter weather (dry skin during the winter months)
o Harsh soaps
o Frequent bathing
o Age

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7
Q

Treatment for asteatotic dermatitis

A
  • Regular lotions may aggravate the condition (need to stay on top of it)
  • Use skin emollients (lanolin, glycerin, urea, lactic acid)
  • Moisturizing soaps
  • Decrease frequency of bathing (not every single day)
  • Humidifiers (especially during the winter)
  • Topical corticosteroids in severe conditions
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8
Q

Atopic dermatitis

A

AKA – atopic eczema, allergic eczema, atopy

  • Chronically relapsing skin eczema that may begin in infancy, childhood, adolescence or adulthood.
  • Most cases present at an early age
  • Frequently a family history
  • Associated allergic rhinitis and asthma
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9
Q

Pathology of atopic dermatitis

A

Stratum corneum contains 3 types of lipids
o Ceramides
o Cholesterol
o Free fatty acids

Thought to be due to barrier abnormalities
o Possible filaggrin mutation
o Insufficient ceramides

These factors make skin more likely to break down

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10
Q

Symptoms of atopic dermatitis

A
  • Erythematous papulovesicular eruption that evolves into dry, scaly dermatitis with accentuated skin lines
  • Becomes lichenified plaques over time
  • No primary lesion in atopic dermatitis and diagnosis made by combining clinical symptoms…
    o Extremely pruritic rash
    o Chronic or recurrent (sometimes in the same areas)
    o Personal or family history of asthma, seasonal allergies and eczema
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11
Q

What factor determines the distribution of atopic dermatitis on the body?

A

AGE!

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12
Q

Distribution of atopic dermatitis in 0-2 year olds

A
  • Face, wrists, extensor surface of arms and legs

- Papulovesicular lesions

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13
Q

Distribution of atopic dermatitis in 2-12 year olds

A
  • Flexor surfaces, face, wrists, ankles

- Maculopapular lesions that are extremely puritic

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14
Q

Distribution of atopic dermatitis in adolescents and adults

A
  • Flexor surfaces, face, wrists, knees, hands and feet

- Lichenification, xerosis, papulation

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15
Q

Theories of aggravating factors in atopic dermatitis

A
  • Sweat retention and secondary superimposed infection may lead to exacerbations
  • Emotional upsets and increased temperature may also worsen pruritus and the dermatitis
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16
Q

Atopic dermatitis treatment

A
  • Elimination of inflammation and infection – mostly treat the symptoms
  • Hydration (urea or lactic acid)
  • Control factors that cause exacerbation (control stress, environmental allergens, etc.)
  • Topical corticosteroids (low potency for mild to moderate eczema and moderate to potent for lichenified plaques)
  • Antihistamines
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17
Q

Dyshidrotic eczema

A

Recurrent skin reaction on hands and feet (due to sweating)
o Frequently in medial heel region and sole
o Can look very similar to tinea pedis

May be related to atopic dermatitis
o Usually brought on by stress and hyperhidrosis
o Usually worse in the summer

18
Q

Phases of dyshidrotic eczema

A
  • Acute phase

- Chronic phase

19
Q

Acute phase of dyshidrotic eczema

A

o Fluid filled vesicles with hyperhidrosis and pruritis

20
Q

Chronic phase of dyshidrotic eczema

A

o Scaling, fissuring, and erythema with lichenification

o May get secondary bacterial infection due to fissuring

21
Q

Treatment of dyshidrotic eczema

A
  • Wet dressings or soaks to relieve itching (Burrow’s solution helps to dry lesions and reduce perspiration)
  • Topical corticosteroids (use sparingly)
  • Decreasing perspiration (antiperspirants, charcoal inserts for shoes)
  • Do KOH to rule out fungal origin (because if you put a steroid on tinea pedis, it will make it worse)
22
Q

Contact dermatitis subtypes

A
  • Primary Irritant Contact Dermatitis (more common)
  • Allergic Contact Dermatitis (more common)
  • Photoallergic Contact Dermatitis (somewhat rare)
  • Phytophotodermatitis (somewhat rare)
23
Q

Primary irritant contact dermatitis

A
  • Exposed to sensitizing agent for a brief period of time (harsh chemical, dye, etc.)
  • No prior sensitization needed
  • Concentration of irritant must exceed a threshold before a reaction can take place
  • Not immunologically mediated
  • Irritant reaction can occur immediately after contact
  • Comprises 80% of contact dermatitis
24
Q

Allergic contact dermatitis

A
  • Delayed T cell-mediated immune response to antigen – this is a TRUE allergic reaction
  • Type IV hypersensitivity reaction
  • Introduction period of 5-7 days required before first appearance of hypersensitivity
  • Repeated exposure causes response to be more rapid and severe
  • Exacerbated by heat and warmth
  • Often misdiagnosed for tinea pedis
25
Q

Allergic contact dermatitis phases

A
  • Irritant phase (localized erythema)
  • Allergic phase (inflammation and small puritic vesicles and papules)
  • Vesicular phase (bullae formation)
26
Q

Clinical appearance of allergic contact dermatitis

A
  • Difficult to differentiate from irritant contact dermatitis
  • Allergic contact dermatitis appears with erythema, vesiculation and edema
  • Irritant contact dermatitis looks like a burn with large blisters
  • Length of exposure and presentation of symptoms
27
Q

Diagnosis of contact dermatitis

A
  • Suspicion of cause (patient may already know)
  • History
  • Patch test of common skin sensitizers (allergy testing)
  • KOH to rule out tinea pedis
28
Q

Common sensitizers for contact dermatitis

A
  • Rhus plants (poison oak, ivy and sumac)
  • Nickel compounds
  • Rubber compounds
  • Chromates
  • Povidone-iodine
  • DC Yellow No.11 dye
  • Leather dye
  • Lanolin
  • Neomycin
  • Formaldehyde
29
Q

Now we are going to go through a series of comparisons for irritant dermatitis and contact dermatitis

A

We will be evaluating the following criteria

  • Symptoms (acute/chronic)
  • Margination (acute/chronic)
  • Evolution (acute/chronic)
  • Causative agent
  • Incidence
30
Q

Symptoms of irritant dermatitis vs contact dermatitis

A

Irritant dermatitis

  • Acute - stinging then itching
  • Chronic - itching and pain

Contact dermatitis

  • Acute - itching then pain
  • Chronic - itching then pain
31
Q

Margination of irritant dermatitis vs contact dermatitis

A

Irritant dermatitis

  • Acute - sharply defined, confined to the site of exposure
  • Chronic - ill defined

Contact dermatitis

  • Acute - sharply defined, but spreading at the edges
  • Chronic - ill defined, but spreading
32
Q

Evolution of irritant dermatitis vs contact dermatitis

A

Irritant dermatitis

  • Acute - rapid (a few hours after exposure)
  • Chronic - months to years of repeated exposure

Contact dermatitis

  • Acute - delayed (12-72 hours after exposure)
  • Chronic - months or longer with exacerbation after re-exposure
33
Q

Causative agent of irritant dermatitis vs contact dermatitis

A

Irritant dermatitis
- Occurs only above a certain threshold

Contact dermatitis
- Occurs independent of amount used

34
Q

Incidence of irritant dermatitis vs contact dermatitis

A

Irritant dermatitis
- May occur in everyone

Contact dermatitis
- Only occurs in the sensitized

35
Q

Photodermatitis

A
  • Occurs when topical agent gets activated by sunlight

- Uncommon

36
Q

Phytophotodermatitis

A
  • Phototoxic reaction to plants
  • Due to light sensitive compound -
    o Furocoumarins (psoralens)
  • Potential triggers (lime juice, plants of the Apiaceae, or Umbelliferae family such as carrots, parsnip, dill, fennel, celery, anice)
37
Q

Symptoms of phytophotodermatitis

A
  • Lesions appear 8-24 hours after exposure
  • Occur where there was contact with plant and sunlight
  • Get burning sensation, with erythematous irregular patches or streaking
38
Q

Treatment for contact dermatitis

A
  • Eliminate exposure
  • Wet dressings and cold compresses
  • Soak
  • Topical corticosteroids for inflammation (use the least potent steroid that will still be therapeutic)
  • May use oral corticosteroids for extensive dermatitis
  • Antipruritics (calamine lotion)
  • Antihistamines (topical or oral diphenhydramine (Benadryl))
39
Q

Describe wet dressing and cold compresses in the treatment of contact dermatitis

A

o Relieves itching, burning and paresthesia

o Dries secretions and softens scales and crusts

40
Q

Describe soaks in the treatment of contact dermatitis

A 
Aluminum acetate (Burow 's solution) 
-	1:10 mixture for 15-20 minutes
Magnesium sulfate (Epsom salt)
-	2 tablespoons/ pint of H2O

They both have drying effect to dry vesicles and/ or weeping

41
Q

Case of phytophotodermatitis

A

23 year old patient
o Spent 2 days on the beach preparing mojitos (have lime juice)
o 24 hours later developed severe blistering

42
Q

Case of photodermatitis

A
  • Rx from insect repellent and sunlight

#2 Derm (13 decks)

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