inflammatory skin diseases Flashcards
what does the word eczema mean
the greek word for boil over
how common is eczema
5% in children
describe eczema
it is a reaction pattern rather than a specific disease
what does the acute stage of eczema look like
red and weeping
can have serous exudate that can have small vesicles present
what does subacute dermatitis look lik
red skin
less exudate
itchy
crusty
what does the chronic stage of eczema look like
more scaled and leathery
what does eczema look like histologically
oedema in the skin
with fluid filled white spaces
which can cause blisters in the epidermis
what does the subacute chronic eczema look like
the epidermis is thickening and the undulation is pronounced
thick keratin layer
describe atopic eczema
starts in childhood occasionally adults
family history
what is atopic eczema associated with
asthma and hay fever
type 1 HS reaction
define contact irritant dermatitis
direct injury to skin by an irritant
define contact allergy dermatitis
can occur from metals, rubber etc
delayed type 4 HS reaction
what type of HS reaction is contact allergy dermatitis
type IV
describe contact allergic dermatitis
act as haptens which combine the epidermal protein to become immunogenic
describe seborrheic dermatitis
affects sebaceous gland rich areas eg scalp
no known aetiology
describe nummular dermatitis
coin shaped lesions- no known aetiology
how much of the population have psoriasis
1-2% of the population
what does psoriasis look like clinically
well defined red oval plaques on the extensor surface fine silvery scale audpitz signs pitted nails sero negative arthritis
what is audpitz signs
Removal of scale causes small bleeding points
what do we see microscopically in psoriasis
Similar elongation of the undulations in the epidermis
Loss of granular layer
Elongation is very regular
Lots of lymphocytes
Little aggregates- often within the corneal layer
Thinned epidermis
Monroe micro abscesses
Postulates- little pustules can form in the epidermis seen in pustular psoriasis
what is the pathogenesis of psoriasis
autoimmune
not sure yet
think from a trigger eg trauma
what mutation can be seen in psoriasis
PSORS gene- on chromosome 6p2 implicated
comorbidity seen in psoriasis
arthritis
CVD
cancer
treatments for psoriasis
UV light
but it is a risk for non melanoma skin cancers
what is lupus erythematosus
auto immune disorder affecting the CT of the body
what happens in systemic lupus erythematosus
autoantibodies directed at various tissues
may affect any part of the body but importantly kidneys
what do we see on the skin in SLE
discoid LE
in systemic LE what can we see on the skin
visceral disease Red scalp patches on sun exposed skin
scarring
Scalp involvement causes alopecia
Malar rash
what is malaria rash
which is a butterfly shaped rash on the cheeks and nose
what dow e see in systemic LE microscopically
epidermis is thin basal keratinocytes missing oedema basement membrane thickens inflammation underneath- can be around the vessels plasma cell might be prominent lymphocytic
describe dermatomyositis
peri ocular oedema and erythema
erythema in photosensitive distribution
why might adults suffer from dermatomyositis
25% associated with underlying visceral cancers
what do we see histologically in dematomyositis
Do not get immunoglobulins at the base of the epidermis therefore no immunofluorescence
Similar to lupus
how can we detect SLE
immunofluorescence
Created antibody against human antibodies with fluorescent tag:
describe lichen planus
generally in adults
duration 1-2 years
associated with HIV
which HS reaction is lichen planus associated with
type IV HS reaction
what do we see histologically in lichen planus
Missing keratinocytes
Inflammation pronounced
Superficial
what is a bullous disease
formation of fluid filled blisters
what are pemphigus disorders
by a loss of cohesion between keratinocytes resulting in a INTRAepidermal blister
what are pemphigoid blisters
At the bottom of the epidermis
Tense and robust
Can be localised or extensive disease
describe pemphigus blisters
fragile blisters
formed within the epidermis
antibodies to the components to the intercellular junctions
will people have oral manifestations in pemphigus diseases
90% yes
how can we detect pemphigus blisters
immunofluorescence
what can we see histologically in pemphigus blisters
Deposition of these antibodies that causes the epidermis to fall apart
Tombstoning of the epidermis
what is the pathogenesis of pemphigoid blisters
Antibodies forming to the basement membrane
histologically what do we see in pemphigoid blisters
smooth boundary between top and bottom of blisters
a lot of eosinophils
inflammation varies
describe dermatitis herpetiformis
Small itchy blisters
Often young pts associated with coeliac disease
IgA deposition in dermal papillae
what is the histopathology of dermatitis herpetiformis
Neutrophil microabscesess in the dermal papillae
Subepidermal bulla
igA located within the bulla
Neutrophil aggregation at the base
give examples of skin lesions as a manifestation of a systemic disease
acanthuses nigricans- dark warty lesions in armpit
dermatomyositis linked with visceral cancer
dermatitis herpetiformis and coeliac disease
what is dermatomyositis associated with
visceral cancer
what is dermatitis herpetiformis associated with
coeliac disease
what is erythema nodosum associated with
infections elsewhere eg lungs
what is erythema nodosum
red tender nodules on shins
what is pretibial myxoedema seen with
thyroid disease
what are the two forms of chronic idiopathic inflammatory disease
ulcerative colitis
cronhs disease
describe UC
Disease of the colon
Inflammation begins at the rectum and moves through the large bowel
Inflammation is superficial but leads to the mucous membrane being eroded
what are some manifestations seen in UC
Skin-
pyoderma ganrenosum
Joints:
Large joint arthritis
Ankylosing spondylitis
Liver:
primary sclerosing cholangitis
describe crowns disease
May arise form mouth to anus
Inflammation tends to be patchy- skip lesions
Can get fistulas between the Gi tract and the skin or other bits of the organs
what is the histological landmark of crohns disease
non caseating granulomas
what are oral manifestations of crohns disease
deep ulcers
