Dermatology Flashcards
What rash is associated with coeliac disease
dermatitis herpeticum
Describe dermatitis herpeticum rash
Pruritic papulovesicular rash affecting both elbows and back
Underlying mechanism of keloid scars
Excess collagen production (fibroblast)
What is a keloid scar
Raised thickened area at site of previous skin injury
Histology of alopecia
T cells within peribulbar infiltration that release cytokines and chemokines -> reject hair -> hair loss
Aeitology of tuberous sclerosis
mutations of TSC1 gene on chromosome 9 or TSC2 gene on chromosome 16 (most common)
50% autosomal dominant
50% sporadic
What does TSC1 gene code for?
hamartin
What does TSC2 gene code for
tuberin
Pathophysiology of tuberous sclerosis
Hamartin and tuberin form a regulatory complex that acts to limit the activity of rapamycin complex 1
Mutations here lead to poorly controlled cell growth
Clinical presentation of tuberous sclerosis
Epilepsy
Learning disability
Hypomelanotic macules, ash-leaf macules, shagreen patches, adenoma seabeecum
Eyes -retinal hamartomas
Cardiac rhabomyomas
Investigations
Wood light
Risk factors for psoarsis
Positive family history
Genetics - guttate psoarsis ass. with HLA-BW17, HLA-BLA13, HLA-C6
Infection
Sunlight
What is Koebnar phenomen
psoarsis occurring on pervious areas of trauma
Pathophysiology of psoarasis
T cell immune-mediated autoimmune disorder
T helper cells produce inflammatory cytokines - inc. interlukin-IL 17 AND IL 22 and tumour necrosis factor
These stimulate proliferation of. keratinocytes and production of dermal antigen adhesion molecule in local blood vessels -> stimulates cytokine release
Increases skin cell turnover - immature skin cells migrate to surface with dead skin cells remaining ->. plaque lesions
Typical tinea corporis lesions
annular, erythamatous, scaly pruritic border with clear centre