Contact Dermatitis

Question 1

dermatitis or eczema derinition

Answer 1

pattern of cutaneous inflammation that presents with:
ACUTE PHASE: erythema, vesiculation & pruritis

CHRONIC PHASE characterized by dryness, scaling,lichenification, fissuring & pruritis

Question 2

Types of dermatitis (5)

Answer 2

many types, including

1. Seborrheic
2. atobic
3. dyshidrotic
4. nummular
5. CONTACT DERMATITIS

Question 3

Contact dermatitis:
definition
types

Answer 3

skin condition created by a reaction to an externally applied substance

2 types of contact dermatitis:

• IRRITANT contact dermatitis (ICD)
• ALLERGIC contact dermatitis (ACD)

Question 4

When does allergic contact dermatitis occur?

Answer 4

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

Question 5

Most common cause of allergic dermatitis

Answer 5

Rhus dermatitis from:

poison ivy, poison oak, or poison sumac (all contain the resin urushiol)

Question 6

Other common causes of allergic contact dermatitis (8)

Answer 6

1. Fragrances
2. Formaldehyde
3. Preservatices
4. Topic antibiotics
5. Benzocaine
6. Vitamin E
7. Rubber compounds
8. Nickel

Question 7

Main sx of allergic contact dermatitis

Answer 7

PRURITIS (itching)

Question 8

Allergic contact dermatitis presentation

Answer 8

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.)

Question 9

Poison oak leaves (U) characteristics

Answer 9

• 3-7cm
• lobulated notched edges
• groups of 3,5 or 7
• grows on bush like plants
• turn colors in autumn

Question 10

Poison ivy leaves (U) characteristics

Answer 10

• 3-15cm in length
• notched edges
• groups of 3s
• grows on hairy-stemmed vines or low shrubs
• turn colors in autumn

Question 11

Rhus allergy typical presentation:

• initial
• subsequent

Answer 11

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

Question 12

Rhus allergy appearance

Answer 12

• lesions begin as erythematous macules that become papules or plaques
• blisters often form over 1-2d

Question 13

Rhus dermatitis what aids in dx?

Answer 13

linear streaks aid in dx (from the linear contact of the plant)

fomites can be contaminated by the plant oil lead to recurrent eruptions

Question 14

Rhus dermatitis tx: most patients

Answer 14

most patient need MINOR supportive care:

1. topical steroids for local involvement
2. topical or oral antihistamines for pruritis
3. oatmeal soaks/calamine lotion may soothe weeping erosions

Question 15

Rhus dermatitis: severe involvement tx

Answer 15

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

Question 16

Rhus allergy prevention (3)

Answer 16

1. avoid the plants
2. wash clothing, shoes & objects after exposure (within 10 mins if possible)
3. apply barrier: clothing, OTC produces which bind resin more than skin

Question 17

Eyelid allergic contact dermatitis:
description
cause(s)

Answer 17

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

Question 18

evaluation of dermatitis

Answer 18

1. comprehensive hx
2. complete derm assessment of pt
3. shape, configuration & location of dermatitis are useful clues to ID culprit
4. elimination of suspected trigger may be both dx & therapeutic
5. in chronic cases, PATCH TESTING is necessary to ID specific allergens

Question 19

What testing is necessary to identify specific allergens in chronic dermatitis?

Answer 19

patch testing

Question 20

Hx: what to ask in addition to dermatitis-specific hx (4)

Answer 20

1. daily skin care routine
2. all topical produces
3. occupation/hobbies
4. regular & occasional exposures (e.g. lawn care products, animal shampoos)

Question 21

Pt has allergic contact dermatitis. In addition to avoiding the allergen, what tx would you recommend?

Answer 21

Desonide cream (for a limited period: twice daily for 1 week, followed by once daily for 1-2 weeks, then d/c)

Question 22

Class 1, 2 or 3 steroid negative effects

Answer 22

regular use->steroid atrophy (thinning & easy bruising/purpura) & hypopigmentation in darker sking types

Question 23

Which steroids to use on the face?

Answer 23

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

Question 24

Patch testing:
use
process

Answer 24

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

Question 25

When to refer allergic dermatitis pts for patch testing? Positive reaction on patch testing indicates?

Answer 25

when allergen is unclear or the dermatitis is chronic + rxn DOES NOT mean pts rash is due to that allergen; elimination of the rash with removal of allergen confirms the clinical relevance of the positive patch test

Question 26

Treatment of ACUTE phase of allergic contact dermatitis

Answer 26

depends on severity of dermatitis: 1. MILD-MOD cases: topical steroids of MED-STRONG potency for a limited course 2. short course of systemic steroids may be required for acute flares 3. oatmeal baths or soothing lotions can provide further relief in mild cases 4. wet dressings help when there are extensive oozing & crusting

Question 27

Which allergic contact dermatitis cases should be referred to a dermatologist?

Answer 27

CHRONIC cases or pts w/dermatitis involving OVER 10% of BSA

Question 28

What is the 2nd most common allergic contact dermatitis?

Answer 28

NICKEL DERMATITIS | 2nd to Rhus dermatitis

Question 29

Latex allergy presentation

Answer 29

either delayed or immediate hypersensitivity: DELAYED HYPERSENSITIVITY: pts develop an allergic contact dermatitis, often presents on dorsal surface of the hands IMMEDIATE HYPERSENSITIVITY: immediate sxs such as burning, stinking or itching with or without localized urticarial on contact w/latex proteins -may include disseminated urticarial, allergic rhinitis and/or anaphylaxis

Question 30

Irritant contact dermatitis: definition

Answer 30

inflammatory rxn in skin resulting from exposure to a substance that can cause an eruption in most ppl who come in contact with it -no previous exposure is necessary -may occur from a single application w/severely toxic substances but most commonly results from mildy irritating substances (e.g., soaps, detergents)

Question 31

Irritant contact dermatitis influencing factors (2 main categories)

Answer 31

a multifactorial dz where both exogenous (irritant & environmental) & endogenous (host) elements play a role

Question 32

most important exogenous factor influencing irritant contact dermatitis

Answer 32

inherent toxicity of the chemical for human skin

Question 33

2 endogenous factors influencing irritant contact dermatitis

Answer 33

1. site differences in barrier fxn, making the face, neck, scrotum & dorsal hands more susceptible 2. ATOPIC DERMATITIS is a MAJOR RISK FACTOR for irritant hand dermatitis b/c of impaired barrier fxn and lower threshold for skin irritation

Question 34

Irritant Clinical Dermatitis: Clinical Findings

Answer 34

mild irritants produce erythema, chapped skin, dryness & fissuring after repeated exposures over time - PRURITIS can range from mild to extreme - PAIN (C) symptom when erosions & fissures are present - severe cases present w/EDEMA, EXUDATE & TENDERNESS - potent irritants produce painful bullae within hours after exposure

Question 35

Irritant Contact Dermatitis evaluation & tx

Answer 35

1. mainstay tx: ID & avoid potential irritant 2. topical steroids to reduce inflammation & emollients to improve barrier repair (U) recommended 3. refer to derm for pts not improving w/removal of irritant or in severe cases 4. PATCH testing in occupational cases w/suspected chronic irritant dermatitis TO EXCLUDE ALLERGIC CONTACT DERMATITIS

Question 36

Irritant contact dermatitis prevention

Answer 36

1. once causal irritant is identified, educate pts abt irritant avoidance, including everyday practices that may CAUSE or CONTRIBUTE to ICD 2. use personal protective equipment (eg protective gloves for any wet work 3. instead of soap, use less irritating substances such as emollients & soap substitutes when washing 4. be careful for several months after dermatitis heals b/c skin remains vulnerable to flares of dermatitis for a long time