1. Contact Dermatitis

2. Pathogenesis of Dermatitis
Irritants
Allergens
type 1&4
Infection
Endogenous factors

3. Contact Dermatitis Acute -redness, itching, vesiculation
Chronic - scaly desquamation
Site and morphology determined by causative exposure
Irritant - caustic agents or detergents -hands
‘Allergic’ - rash 6-12 hours peaking at hours

4. Irritant contact dermatitis
Skin damaged directly by the irritant
soaps, detergents, water, solvents, dry atmosphere etc
very, very common
at least 5% of the population suffer from hand dermatitis
Treat with emollients/moisturisers

5. Delayed “allergy” Takes the immune system a few hours to react
Allergic contact dermatitis (ACD)
Common causes:
nickel
fragrances
rubber additives
preservatives
plants
medicaments etc

6. Sensitizers Nickel - wear >18 carat gold
Rubber accelerators in elastic, gloves, shoes
Permanent hair dyes -paraphenylenediamine
Fragrances eg Balsam of Peru and cinnamic aldehyde present in cosmetics, soaps, perfumes and toothpastes - use ‘fragrance free’ products not just unscented.
Adhesives and Varnishes
Latex, Formaldehyde and Chromates
Benzocaine and neomycin in topical medications

7. ACD
Nickel allergy involves ears, skin under buckles and often the hands; accidental spread from the hands can affect the face
Hair products - dyes and sprays - affect the face, neck and ears.
Dyes in socks and shoes affect the feet.
Medications for the treatment of leg ulcers can cause dermatitis of the legs