Psoriasis Flashcards
Explain 6 ways in which psoriasis affects nails
1 m/c nail finding → thimble pitting
2 onycholysis → separation of nail from nail bed
3 salmon patches of nail bed
4 subungual hyperkeratosis → keratinous material under nail plate
5 oil drop sign → staining of nail bed
6 thickening & tunneling of nail plate
Define psoriasis
Genetically determined
T cell mediated
Chronic
Relapsing
Skin dis
Unknown etiology
Define lesions?
Skin lesions are → erythrosquamous
Means it involves both > vasculature (erythema)
> epidermis ( increased scale formation)
Worsens in winter
+ve family history in > 50%
HLA asso.?
HLA CW 6
What is basic underlying pathologic defect ?
Increased epidermal proliferation rate
Normal skin →27 days.
Psoriatic skin → 4 days
Aggravating factors?
Sepsis
Stress
Cold injury» shivering
Trauma
Drugs → beta blockers
lithium
Antimalarial’s
ibuprofen
stoppage of steroids
Histo features?
Munro microabstasses → neutrophils in stratum corneum
Spongiform pustules of kogoj → neutrophils in stratum spinosum
Parakeratosis
Absent granular layer
Lesion looks like?
Does it itch?
Silvery mica scales → scales typically absent in groin & flexures
As epidermal mass is increased 3-5 times
Mild / No itching » variably pruritic
Onset?
Gender preponderance?
2nd-3rd decade
More common in males
Common sites?
Extensor aspects → elbow, knees, trunk » back & lumbo sacral area
scalp, hands
Signs in psoriasis?
Auspitz sign
Bulkeley’s membrane
Grattage test
Woronoff’s ring
Köbner / isomorphic phenomenon
Candle grease sign (tache de bougie)
Describe auspitz sign
When scales are scrapped → pinpoint bleeding » from dilated superficial capillaries occurs through Bulkeley’s membrane
Describe Bulkeley’s membrane ?
Removal of scales reveal a glistening red membrane of bulkeley
Grattage test
On scratching the lesion → mila like scales appear
Woronoff’s ring?
Whitish halo around the lesion