allergic contact dermatitis

Question 1

define allergy

Answer 1

exaggerated reaction of immune system following contact with certain foreign substances

Question 2

define allergen

Answer 2

Allergen: substance that causes or elicits the allergic reaction

Question 3

Red, itchy, weepy patches of skin. Can occur in different conditions, including allergic contact, irritant contact and atopic dermatitis

Answer 3

eczema

Question 4

What is allergic contact dermatitis?

Answer 4

An allergic reaction to something that comes in contact with the skin

Question 5

who gets allergic contact dermatitis?

Answer 5

Potentially anyone Genetic predisposition

Atopy: tendency towards developing allergies, asthma, hay fever, dermatitis

Question 6

How does allergic contact dermatitis happen?( two steps)

Answer 6

Two-step process
Becoming allergic (sensitization or induction)
Developing the rash after re-exposure (elicitation)

Question 7

what is step 1 of allergic contact dermatitis? what can predispose to step 1?

Answer 7

Step 1: Becoming allergic

Sensitization: first contact
Must first contact an allergen to develop allergy
Certain conditions predispose to development of allergy
open skin: loss of barrier function

Question 8

what is step 2 of allegic contact dermatitis?

Answer 8

Step 2: developing the rash

Once sensitized, immune system “remembers” allergy
When contact with allergen recurs (re-challenge), immune memory recalls allergy and sets allergic reaction in motion: elicitation

Question 9

what are the sign and symtpoms of the rash of acute allergic contact dermatitis (4)

Answer 9

itchy
red
crusting / oozing
blisters

Question 10

what are signs and symptoms of chronic allegic contact dermatitis?

Answer 10

Chronic allergic contact dermatitis
+/- itch
less red
hyperpigmentation( hall mark of inflammation in darker skinned ppl)

thickened skin
fewer blisters, may see more cracking

Question 11

ACD usually affects skin __________ with allergen

Answer 11

ACD usually affects skin at site of contact with allergen

Question 12

ACD is a ______reaction

When do symptoms develop?

with repeated exposure, describe the rxn?

how long does the rash last?

which symptoms are not present?(2)

Answer 12

ACD is a delayed-type hypersensitivity reaction

Symptoms develop 24-48+ hrs after exposure
With repeated exposure, reactions are quicker and more intense
Rash lasts 7-14 (or more) days
Usually **no hives, wheezing **

Question 13

what in posion ivy causes ACD?

when does the rash appear? how long does it last?

what are the symtoms?

what is the pattern of the rash?

Answer 13

Allergic reaction to oil (urushiol) in plant

Rash appears 1-4 days after exposure
Lasts 7-21 days
Symptoms range from mild itch to severe itch with blisters
Linear pattern suggests “outside job”

Question 14

Can posion ivy rash be spread in the blister fluid?

Answer 14

NO! Only contact with the oil will spread the rash

Question 15

how can urushiol be spread?(3 ways)

Answer 15

Urushiol is present in vines and can be spread by contact, or in air by burning

Question 16

what causes allegic contact dermatitis?

Answer 16

Usually **small molecular weight chemicals **

Question 17

what are type of rxn are food and environmental allergens morel likely to cause? what are the symptoms for these?

Answer 17

Foods and environmental allergens (dust, molds, pets, etc) more likely to cause immediate-type hypersensitivity reactions

symptoms: sneezing, cough, hives

Question 18

common allergens: what are they?(6) where are they?

Answer 18

Nickel and other metals
Fragrances
Preservatives
Compounds in rubber products
Topical antibiotics (neomycin, bacitracin)
Plants

Question 19

nickel allergy: how common? where is expsoure most liely?

Answer 19

Nickel allergy one of most common allergies
Up to 15% in US
Incidence increasing
Exposure to nickel common in jewelry
Body piercing thought to contribute

Question 20

where is nickel most likely?

Answer 20

jewelry, metal objects ( paper clip, keys coins)

clothing: jean snaps, zippers, eyelets

medical devices including artificial joints, pacemaker

Question 21

which test is used to test for nickel in products?

Answer 21

Dimethylglyoxime test: pink color indicates presence of nickel

The dimethylglyoxime – ammonia test is able to detect nickel content in a metal object.

Question 22

some foods that contain nickel?

Answer 22

Cocoa & dark chocolate
Beer
Oatmeal
Oysters
Dry legumes
Asparagus
Hazelnuts
Sunflower seeds
Gelatin
Soybeans
Baking powder

note: nickel in some multivitamins

Question 23

recommendation for nickel allergy?

Answer 23

Avoid exposure to nickel-containing metals
Cover metals with plastic, etc.
If piercing, use non-nickel containing metals
Watch for reactions to other metals: cobalt, chromium
Low-nickel diet may benefit some, but not often recommended
Legislation to minimize nickel exposure in common items

Question 24

frangance allergies:

Answer 24

Allergies to fragrances common
Second most common allergy
Up to 10% patients in allergy clinics
Many different components of fragrances can cause allergy
Testing usually done in “mixes”
Can react both to natural and synthetic fragrances

Question 25

where are most fragrances found?

Answer 25

**Most personal care products contain fragrances** perfumes, colognes essential oils household products (room fresheners, candles) medicated creams, medicaments note: unscented products have masking fragrances, even fragrance free products have traces of fragnaces if not used for that purpose

Question 26

where are allergies to fragrances most common on body? what test is recommended whne using a new produtc?

Answer 26

Allergic reactions to fragrances most common on **face, neck, skin around the eyes** Some fragrances are used as flavoring agents and rarely cause allergic reactions when ingested cinnamon flavorings Performing a **“use test”** recommended when using a new product

Question 27

function of preservatives in cosmetic, pharmaceuticals and industrial applications?

Answer 27

prevent bacterial and fungal overgrowth

Question 28

what are the most commonly used preservatives? (list a few)

Answer 28

Commonly used preservatives **formaldehyde** formaldehyde-releasing chemicals methylchloroisothiazolinone/methylisothiazolinone methyldibromoglutaronitrile phenoxyethanol parabens

Question 29

KNOW: chemicals that release formaldehyde upon contact with skin?

Answer 29

Chemicals that release formaldehyde upon contact with the skin **Quaternium-15 DMDM hydantoin Imidazolidinyl urea Diazolidinyl urea 2-bromo-2-nitropropane-1,3-diol** Can be allergic to these individually or cross-react if allergic to formaldehyde

Question 30

where can preservative alleriges occur? is testing needed? what is tx?

Answer 30

* *Reactions can occur at site of contact or be relatively diffuse** * *Testing is usually needed t**o detect and confirm allergy * *Avoidance is necessary once sensitized**

Question 31

types of reactions to latex rubber products?

Answer 31

**Immediate-type reactions to latex proteins: ** hives, itching, wheezing or anaphylaxis **Delayed-type reactions to chemical additives in rubber products** eczematous reactions

Question 32

what can synthetic rubbber products(such as nitirle) contain?

Answer 32

Synthetic rubber products (such as nitrile) can **contain allergenic accelerators and other chemicals**

Question 33

latex allergy: 1. what type of allergy 2. how do they occur and what type of rxns? 3. have latex allergies improved?

Answer 33

**1. Immediate-type hypersensitivity** reactions to latex 2. **Reactions originally to powdered latex gloves** Latex proteins ad**here to powder and are aerosolized Reactions ranged from itching to death** **3.Incidence has improved through elimination of powder, production of “better” gloves**

Question 34

KNOW: what are three common rubber allergens?

Answer 34

Common rubber allergens include **thiurams thiazoles carbamates**

Question 35

t/f. Use of chlorine bleach makes carbamates in elastic more allergenic

Answer 35

true

Question 36

two topical antibiotics that elicit allergic rxns/

Answer 36

neomycin bacitracin

Question 37

topical antibiotic allergic rxns can be confused for \_\_\_\_\_\_\_\_\_\_ the use of topcial antibiotics on open skin may increase\_\_\_\_\_\_\_\_

Answer 37

**Reactions may be confused for infection** **Use of topical antibiotics on open skin (dermatitis) may increase chance of developing allergy** Two antibiotics may cross react

Question 38

whar are the 4 most common plant allergens? (PACT)

Answer 38

Primrose Alstroemeria Chrysantemum Tulip

Question 39

testing for ACD. Experienced dermatologists predict relevant allergens only \_\_\_\_\_of time _________ does not give info as to likely cause _______ is gold standard

Answer 39

Experienced dermatologists predict relevant allergens **only 50% of time** **Skin biopsy does not give info as to likely cause Patch testing is gold standard**

Question 40

which allergy test used for immediate-type hypesensitivity? which allergic test used for delayed-type hypersensitivity?

Answer 40

**Prick (or scratch) testing tests for immediate-type hypersensitivity** detects allergies to foods, trees, grasses, molds, pets **Patch testing tests for delayed-type hypersensitivity reactions** Chemicals, metals, preservatives, fragrances, etc.

Question 41

how do you tx allergic contact dermatitis?

Answer 41

**Symptomatic relief with cool compresses, oatmeal bathes, calamine lotion** A**void Caladryl or any product with topical Benadryl (diphenydramine) which is potent sensitizer** Oral antihistamines generally OK Topical corticosteroids **If oral corticosteroids needed, treat for at least 2-3 weeks in most cases**

Question 42

tx of ACD: once dx is made ________ is only tx. do allergy shots exist?

Answer 42

**Once diagnosed, avoidance is the only “treatment”** **There are no consistently effective desensitization methods for delayed-type hypersensitivity reactions No “allergy shots”**