Week 6 - Allergies at Home & Work Flashcards
What is the difference between Contact Dermatitis (ACD) and Atopic Dermatitis?
Inflammation of the skin due to an EXTERNAL cause vs
Skin reaction due to INTERNAL causes. (e.g. eczema)
What are the 2 types of contact dermatitis?
- Irritant Contact Dermatitis - direct caustic effect of the substance.
- Allergic Contact Dermatitis - Typ 4 immune hypersensitivity reaction.
What substances most commonly cause irritant dermatitis?
- Soaps
- Detergents
- Solvents
- Abrasives
- Alkalis
- Acids
- Cement
- Cutting oils
- Plants
- Dust
What substances most commonly cause Contact Allergic Dermatitis?
- Nickel
- Chromate
- Thiuram - rubber in shoes
- p-tert-Butylphenol-formaldehyde resin -adhesive in shoes.
How do you manage allergic contact dermatitis?
- Detect the sensitising agent -Patient History!
- Settle down the dermatitis
- Patch Testing
- Counselling onavoidance of allergens.
What is the patch testing?
- Used to diagnose alleric contact dermatitis
- European standard Battery Test (35-38 allergens)
- It is read at 48hours and then again at 72-96 Hours for late reactions.
- There can be specialist ones for hairdressers, florists, dental etc.
What is difficult about interpreting patch tests?
- False positives can occur
- Irritant reactions can be confused with allergic ones.
- Multiple reactions angry reactions can inflame the back making interpretation impossible.
Who should be patch tested?
Any patient with unusual eczema:
- eyelid,face,perioral
- otitis externa
- hand/foot dermatitis
- perianalor genital eczema
- asymmetrical patterns
- Sudden worsening of controlled eczema
What are the 3 common causes for hand dermatitis?
- Irritant Contact Dermatitis -powders or soaps
- ACD - usually due to thiuram (patch test)
- Type 1 Allergy - latex. (RAST test)
If someone has unilateral hand dermatitis, what should you consider?
Tinea Infection
What is the chemical in hair dye that can cause an allergic contact dermatitis?
PPD
(Paraphenylenediamine)
What must you advise someone who has had a PPD allergy to not do?
Get their hair died or get tattos.
Steroid allergies can occur.
What is used in patch tests to see if there is an allergy?
Tixocortol pivalate
If the patch test is positive to Tixocortol pivalate, what steroids can and can’t they use?
- Avoid Dermovate and Hydrocortisone
- Use Betnovate and Mometasone.
What are the common allergens found in makeup?
Quaternium-14
Kathon CG
