Eczema / Dermatitis Flashcards
What is eczema?
Common
disparate group of skin diseases
Unified by the presence of itch
What is the classification of eczema according to causative factors?
Exogenous / contact
ALLERGIC vs NON ALLERGIC (IRRITANT) - Allergic eczema Irritant eczema MOST COMMON Photodermatitis Infective eczema
Endogenous / constitutional
ATOPIC vs NON ATOPIC - Atopic eczema Seborrhoeic eczema Discoid eczema Pompholyx Gravitational eczema Asteatotic eczema Neurodermatitis (lichen simplex chronicus) Juvenile plantar dermatitis Napkin dermatitis
What are the clinical features of acute, chronic and subacute eczema?
NOT CLEARLY DEMARCATED ITCHY Erythema Edema Papules/ vesicles/blisters Exudates ( weeping and crusting) May spread
Chronic eczema / dry eczema - Same as acute eczema Less vesicular and exudates SCALING pigmented thickened ACANTHOSIS Fissures Excoriations Lichenification
Features of both
What is the pathogenesis of eczema?
Hallmark is the activated keratinocytes
Initially stratum corneum is intact
So appears red and smooth edematous
CELL RELATED
Increased proliferation of basal cells causes epidermal thickening (ACANTHOSIS) and SCALING
CYTOKINES RELATED
Increased Cytokines cause edema, blistering and weeping and ITCHING
High levels of interleukin 1 from epidermal damage
Interleukin 8 chemotaxis causes characteristic epidermal neutrophil infiltration
Gamma interferon causes perivascular lymphocytic infiltration
What is the histological sequence of eczema?
Acute stage - Epidermal edema (SPONGIOSIS) Vesicles Coalesce to large blisters or rupture
Chronic stage - Less spongiosis and vesicles Thick s spinosum ACANTHOSIS Thick s corneum HYPERKERATOSIS vasodilation with lymphocytic infiltration LICHENIFICATION FISSURING
What are the complications of eczema?
Skin related - Heavy bacterial colonization Overt infection (seborrhoeic, discoid, atopic) Dissemination (gravitational)
Quality of life related - Itchiness Sleepless Job Sports Sex
What are the DDx for eczema?
All Erythematosquamous eruptions
- Psoriasis Scabies Lichen planus Lichenoid drug eruptions Tinea Palmoplantar pustulosis Angioedema Erysipelas Pityriases Dermatitis herpetiformis
What are the investigations for eczema?
Patch testing to confirm allergic contact dermatitis
Patch testing for superimposed contact dermatitis in gravitational eczema
Prick testing and IgE assay for atopic eczema
Culture and scraping microscopy
What is the treatment for acute eczema?
Rest
Compression + antiseptic soaks
Steroid creams
NO OINTMENTS
What is the management for allergic contact dermatitis (type 4 hypersensitivity)?
Identify and remove contact with allergen
Topical corticosteroids
What are the common allergens for contact dermatitis?
METALS -Cr Ni Co COSMETICS -fragrances, hair dye PPD, lanolin PRESERVATIVE in shampoo -formaldehyde, chlorocresol MEDICAMENT in steroid creams, LA -neomycin, quinoline, benzocaine RUBBER -mercapto mix, Thiuram mix, carba mix PLANTS
RESINS
-epoxy resin, colophony plasters
What is atopic dermatitis?
Chronic Pruritic Dermo-epidermal inflammation With family history of asthma, allergic rhinitis Develops in very young age
Preventable by perinatal probiotics
What are the clinical features of atopic dermatitis?
Infants-
face acute eczema
Children-
flexural subacute eczema
Adults-
flexural chronic eczema
What are the complications of atopic dermatitis?
Secondary infection
- eczema herpeticum
- viral warts
- molluscum contagiosum
- folliculitis
- impetigo
Stunted growth
What is seborrhoeic eczema?
Chronic Red scaly Inflammatory eruption Mainly over scalp and face Common in adult males and infants
3 common patterns
- face scalp retroauricular
- presternal interscapular intertriginous
- flexural
What is discoid eczema?
Multiple Coin shaped Vesicular or crusted Itchy Plaques Commonly in middl aged males
What are the common areas for lichen simplex?
Women- nape of neck
Men - legs
Both sexes- anogenital area
