Psoriasis

Question 1

what is psoriasis?

Answer 1

chronic inflammatory autoimmune disease

Question 2

histological features of psoriasis?

Answer 2

epidermal hyperplasia
presence of neutrophils in keratin layer (due to complement mediated attack on keratin layer)
parakeratosis
acanthosis
psoriasiform elongation of rete ridges
thickened prickle layer, thin basal layer
corneal abscess

Question 3

what causes psoriasis?

Answer 3

immunological response to pathogen or the body’s own cells which doesn’t stop when pathogen is destroyed leading to excessive inflammation and chronic skin damage
inflammation leads to dilation of blood vessles in DEJ which delivers immune cells (meutrophils) to the keratin layer
this inflammation causes keratinocytes to proliferate quickly (4 days compared to normal 28)

Question 4

what features are seen in these quickly differentiated keratinocytes in psoriasis?

Answer 4

ticker, produce more keratin

parakeratosis (maintain nuclei)

Question 5

symptoms of psoriasis?

Answer 5

flattened plaques with silver scale over inflamed red patches
auzpitz sign
nail changes
- onycholysis
- dystrophe
- pitting
- subungual hyperkeratosis

Question 6

name 4 other types of psoriasis?

Answer 6

guttate (after strep throat)
erythrodermic
pustular
inverse

Question 7

how does guttate psoriasis present?

Answer 7

small red individual spots on trunks and limbs

post streptococcal infection

Question 8

how is psoriasis diagnosed?

Answer 8

mostly clinical diagnosis

tissue biopsy rarely needed but can be used to show classical skin changes

Question 9

how is psoriasis treated?

Answer 9

vit D analogues
- calcipotriol
- calcitiol 
coal tar (messy)
dithranol
steroids (betnovate for flares)
emollients always given
for severe, resistant cases
- narrowband UVB and PUVA
- immunosuppression (methotrexate)
- targeted biological agents