Inflammatory Skin Disease Flashcards
What is rosacea
A condition where blood vessels of the face dilate.
Cause of rosacea
Unknown!
Certain triggers:
sunlight, alcohol, spicy food, stress
Presentation of rosacea
Fixed central erythema of face Mild or moderate papules pustules Rhinophyma - skin thickening of nose Telangiectasia Ocular involvement - blepharitis, keratitis, conjunctivitis
Ix of roacea
Clinical diagnosis
Tx rosacea
Topical Abx for localised disease:
- topical metronidazole
- azelaic acid
- brimonidine gel
Systemic Abx for more severe disease:
- tetracycline
- isotretinoin
3 main autoimmune causes of skin blistering
Pemphigus
Bullous pemphigoid
Dermatitis Herpetiformis
What skin level does blistering in pemphigus occur in
Intra-epidermal
What skin level does blistering in bullous pemphigoid occur in
Sub-epidermal
What skin level does blistering in dermatitis herpetiformis occur in
Sub-epidermal
Investigation for autoimmune causes of blistering
Biopsy with immunofluorescence
Most common autoimmune bullous disease
Bullous pemphigoid
Presentation of bullous pemphigoid
Large tense bullae on normal skin or erythematous base
Bullae burst to leave erosions - no scarring
Itchy erythematous plaques and papules may preceed bullae formation by 3-4 months (so may be the only presenting feature!)
How many biopsies are taken for the investigation of bullous pemphigoid and where are they taken from
1 for histology - taken from a small intact blister
1 for immunofluoresence - taken from normal skin adjacent to blister
Pathogenesis of bullous pemphigoid
Patients circulating IgG antibodies react with antigens in the BM and hemidesmosomes anchoring basal cells to BM
results in complement activation and deposition around the BM
Histological appearance of bullous pemphigoid
Subepidermal bullae with lots of eosinophils
IMF appearance of bullous pemphigoid
Linear deposition at DEJ
Tx of bullous pemphigoid
Localised disease:
- topical steroids (clobetasol - v potent)
- topical tacrolimus
Generalised disease:
- oral steroids (prednisolone) (0.5-1mg/kg) - 40-80mg/day
prognosis of bullous pemphigoid
chronic and self-limiting
most have remission in several months
What age group of patients usually get bullous pemphigoid
elderly
What age group of patients usually get pemphigus vulgaris
Middle aged
presentation of pemphigus vulgaris
flaccid blisters that can be burst easily to form erythematous erosions
most common locations for pemphigus vulgaris to present
face, scalp, axillae, oral mucosa, groin
What is Nikolsky sign
firm pressure to the top layer of skin detaches the top layer
- positive in pemphigus
- negative in bullous pemphigoid
Most common complication of pemphigus vulgaris
secondary infection of deroofed blisters
Histological appearance of pemphigus
cleavage within epidermis with eosinophil infiltration
Pathogenesis of pemphigus vulgaris
IgG antibodies are directed against intercellular adhesions - acantholysis
Immunofluorescence of pemphigus vulgaris
“chicken wire” appearance - due to acantholysis - lysis of intercellular adhesion sites
Tx of pemphigus vulgaris
Localised disease:
- topical steroids
Systemic disease (more likely to need this): - oral steroids - prednisolone \+/- azothioprine dapsone ciclosporin plasmapharesis
what is dermatitis herpetiformis
autoimmune blistering disorder associated with COELIAC DISEASE
Common sites of involvement of dermatitis herpetiformis
extensor aspects of elbows and forearms
buttocks and scapulae
extensor aspects of knees
face and scalp
presentation of dermatitis herpetiformis
small blisters on erythematous urticarial base
itch - precedes blistering
excoriations - burst blisters
grouping of lesions (like herpes)
Ix for dermatitis herpetiformis
Coeliac serology
Skin biopsy with immunofluorescence
Histological appearance of dermatitis herpetiformis
Subepidermal blister
microabscesses in dermal papillae
Immunofluorescence appearance of dermatitis herpetiformis
granular IgA deposits in dermal papillary
Tx of dermatitis herpetiformis
gluten free diet
dapsone
complication of dermatitis herpetiformis
small bowel lymphoma
What is psoriasis
chronic relapsing and remitting inflammatory skin disorder where there is HYPERPROLIFERATION OF EPIDERMAL CELLS
Cause of psoriasis
Exact cause unknown
Gene variants + environmental insults
Pathogenesis of psoriasis
Increased number of epidermal cells entering cell cycle from the basal layer - therefore faster epidermal turnover time
Epidermal turnover time in psoriasis
5 days
Normal epidermal turnover time
25 days
Plaques in psoriasis - sterile or non-sterile
STERILE!! swabs will grow nothing if pustules are present