Contact Dermatitis Flashcards
dermatitis or eczema derinition
pattern of cutaneous inflammation that presents with:
ACUTE PHASE: erythema, vesiculation & pruritis
CHRONIC PHASE characterized by dryness, scaling,lichenification, fissuring & pruritis
Types of dermatitis (5)
many types, including
- Seborrheic
- atobic
- dyshidrotic
- nummular
- CONTACT DERMATITIS
Contact dermatitis:
definition
types
skin condition created by a reaction to an externally applied substance
2 types of contact dermatitis:
- IRRITANT contact dermatitis (ICD)
- ALLERGIC contact dermatitis (ACD)
When does allergic contact dermatitis occur?
ACD occurs when contact w/a substance elicits a DELAYED hypersensitivity reaction
SENSITIZATION process requires 10-14 days
re-exposure dermatitis appears w/in 12-48h
Most common cause of allergic dermatitis
Rhus dermatitis from:
poison ivy, poison oak, or poison sumac (all contain the resin urushiol)
Other common causes of allergic contact dermatitis (8)
- Fragrances
- Formaldehyde
- Preservatices
- Topic antibiotics
- Benzocaine
- Vitamin E
- Rubber compounds
- Nickel
Main sx of allergic contact dermatitis
PRURITIS (itching)
Allergic contact dermatitis presentation
eczematous, scaly edematous plaques with vesiculation distributed in areas of exposure
ACD is bilateral IF the exposure is bilateral (e.g. shoes, gloves, ingredients in creams, etc.)
Poison oak leaves (U) characteristics
- 3-7cm
- lobulated notched edges
- groups of 3,5 or 7
- grows on bush like plants
- turn colors in autumn
Poison ivy leaves (U) characteristics
- 3-15cm in length
- notched edges
- groups of 3s
- grows on hairy-stemmed vines or low shrubs
- turn colors in autumn
Rhus allergy typical presentation:
- initial
- subsequent
INITIAL episode:
- occurs 7-10d after exposure
- lasts longest (up to 6 weeks)
SUBSEQUENT outbreaks:
- may appear within hours, (U) within 2 days
- Rhus dermatitis lasts from 10-21 days depending on the severity
Rhus allergy appearance
- lesions begin as erythematous macules that become papules or plaques
- blisters often form over 1-2d
Rhus dermatitis what aids in dx?
linear streaks aid in dx (from the linear contact of the plant)
fomites can be contaminated by the plant oil lead to recurrent eruptions
Rhus dermatitis tx: most patients
most patient need MINOR supportive care:
- topical steroids for local involvement
- topical or oral antihistamines for pruritis
- oatmeal soaks/calamine lotion may soothe weeping erosions
Rhus dermatitis: severe involvement tx
may require oral steroids
-in cases of failing potent topical steroids or widespread
IF GIVEN FOR LESS THAN 2-3 WEEKS, PTS may relapse
so DO NOT GIVE SHORT BURSTS of steroids
Rhus allergy prevention (3)
- avoid the plants
- wash clothing, shoes & objects after exposure (within 10 mins if possible)
- apply barrier: clothing, OTC produces which bind resin more than skin
Eyelid allergic contact dermatitis:
description
cause(s)
intensely pruritic
scaling red plaques on UPPER>lower eyelids
often caused by transfer from the hands
(C) causes: nail adhesive/polish, fragrances & preservatives in cosmetics, nickel
evaluation of dermatitis
- comprehensive hx
- complete derm assessment of pt
- shape, configuration & location of dermatitis are useful clues to ID culprit
- elimination of suspected trigger may be both dx & therapeutic
- in chronic cases, PATCH TESTING is necessary to ID specific allergens
What testing is necessary to identify specific allergens in chronic dermatitis?
patch testing
Hx: what to ask in addition to dermatitis-specific hx (4)
- daily skin care routine
- all topical produces
- occupation/hobbies
- regular & occasional exposures (e.g. lawn care products, animal shampoos)
Pt has allergic contact dermatitis. In addition to avoiding the allergen, what tx would you recommend?
Desonide cream (for a limited period: twice daily for 1 week, followed by once daily for 1-2 weeks, then d/c)
Class 1, 2 or 3 steroid negative effects
regular use->steroid atrophy (thinning & easy bruising/purpura) & hypopigmentation in darker sking types
Which steroids to use on the face?
class 6,7 steroids (e.g. desonide) can safely be used intermittently during flares
if topical steroids are used on the eyelid for more than one month, refer to an ophthalmologist for monitoring of intraocular pressure & the development of cataracts
Patch testing:
use
process
used to determine which allergens a pt w/allergic contact dermatitis reacts against
series of allergens are applied to the back & removed after 2 days
on day 4 or 5, patient returns for results
+ rxns show erythema & papules or vesicles
ID of allergens helps pt find products free of those alergens
