Eczema Flashcards
what is the basic pathophysiology of eczema?
barrier dysfunction + inflammation
where is eczema more common in?
cooler climates
more pollution
more so in developed regions - perhalps due to aseptic environments or household cleaning products ?
what gene plays a key role in eczema?
fliggarin gene
what is the pathology of eczema?
spongiosis (oedema iwhtin epidermis)
acanthuses (thickening of epidermis)
inflammation with superficial perivascular lymphohistiocytic infiltrate
what is the distribution of eczema?
flexural
neck, eyelids, face, hands, feet
tends to spare the nappy area due to the area being humid (eczema favours cooler climates)
what are features of chronic changes of eczema?
lichenification
plaques
fissuring
what type of reaction is allergic contact dermatitis? and how long does it take to occur?
type 4 hypersensitivity
24-72 hours to develop a rash/reaction
what cell type is allergic contact dermatitis triggered by?
T cell mediated type 4 hypersensitivity reaction
what causes irritant contact dermatitis?
injury to the skin due to friction i.e. micro trauma or cumulative
environmental factors i.e.;
- cold
- over exposure to water
- chemicals i.e. acids, alkalis, solvents, detergents
occupation
nappy rash
webs of finger due to not drying hands properly
how would you investigate irritant or allergic contact dermatitis?
patch test to identify allergen / trigger
what is the distribution of seborrheic dermatitis?
scalp and proximal flexures
scaling particularly around scalp, eyebrows and ears
what is the cause of seborrheic dermatitis?
malassezia yeast (mites)
what is the treatment for seborrheic dermatitis?
anti - yeast
ketoconazole
what is the presentation of seborrheic dermatitis in adults?
red, sharply marinated lesions covered with greasy looking scales
occur in areas rich in sebaceous glands i.e. scalp, face and upper trunk
what is the presentation of discoid eczema?
circular plaques of eczema
sometimes large patches / plaques
may develop at site of trauma / irritation
what age do you normally find discoed eczema?
adults
often occurs in people who had eczema as a child then went away and has re occurred as discoid after stress etc
what is the presentation of pompholyx / vesicular eczema?
itchy vesicles, very swollen and inflamed these vesicles often burst very painful intensely itchy occurs in the palms and soles
in what age if pompholyx / vesicular eczema most common ?
40s
what type of eczema is characterised by sudden onset of crops of vesicles which are very painful / itchy ?
pompholyx / vesicular eczema
what type of eczema would typically present due to an old lady sitting at the fire place ?
asteatotic eczema
- occurs in ageing population as their skin starts to dry out
- heat triggers it
- most commonly affects shins , lower legs
what is the presentation of venous eczema ?
there is increased venous pressure
oedema
occurs in ankles, lower legs
brown staining of skin
what organism is responsible for eczema herpeticum?
herpes simplex 1 and 2
what is the presentation of eczema herpeticum?
monomorphic pattern of lesions which burst and crust
fever and often unwell
itchy cluster of blisters and erosions
swollen lymph nodes
what is the treatment for eczema herpeticum?
anti virals
what are the treatments for eczema?
treating barrier:
topical emollients; ointments, creams & lotions
treating inflammation:
topical steroids
severe eczema:
ultraviolet light (UVB)
immunosuppression i.e. azathioprine, methotrexate , cyclosporin etc
What test would you carry out for a type 1 hypersensitivity reaction?
Skin prick test
What test would you carry out to determine cause of a type 4 hypersensitivity reaction?
Patch test
What cell types are involved in a type 1 and type 4 hypersensitivity reaction?
Type 1 = mast cells
Type 4 = T cells
If someone presents with hand dermatitis, what signs would you suspect to find on her nails?
Onycholysis
Acute paronchyia
Ridging of the nails
