psoriasis
DESCRIPTION
Psoriasis is a skin diseas. here we discuss etiology, what is it, pathogenesis along with clinical photographs...TRANSCRIPT
Psoriasiform Lesions
Some things common
Epidermal hyperplasia
Elongation of rete ridges
Psoriasis
Psoriasis
Greek word for 'itch'
“chronic
non-infectious
erythematous plaques & papules
silvery scales
extensor distribution”
Psoriasis vulgaris
(common)
Chronic RelapsingPapulosquamous dermatitis
Incidence : 2 %
All Races
More in western people
Mean age - 25 yrs
Chr - 6P21.3
Associated with - HLA-CW0602
(PCR)
How the patient presents ?
Erythematous plaques with
Silver scaling
When the scales are removed …
It bleeds
Auspitz’s sign
Capillaries
Scratch
Which sites are involved ?
Scalp ,
Lips no involved
Oral lesions are rare
5 % cases --- Polyarthritis
Do we know the Cause ?
Trigger factors
TraumaInfectionDrugs : Lithium, iodine , B blockers, Carbamazepine, NSAIDS, ACE inhibitorsClimateHormone, Stress AlcoholSmoking
Lesions after Trauma
(Koebner phenomenon)
30 % cases.
What is the Pathogenesis ?
YY YIts an Immune reaction
“Problem in signal transduction”
Initiation
Cytokine
transcription regulation
problems
Stimulation of immunity by
super antigen
• Problem in signal transduction in between the cells
• Cytokine transcription regulation problems
• Stimulation of immunity by super antigen
Initiation
Blood vessels in the papillary dermis
Disease process starts here
Blood vessels in the papillary dermis
Dilatation and tortuosity
Angiogenesis (TGF alfa, IL 8 )
Size of microcirculation Expands
New vessels bring T lymphocytes
Lymphocyte recruitment in papillary dermis
(PAF, LB4)
Lymphocytes come and bind to endothelial
cells in venules of papillary dermis
Even the expression of
adhesion molecules is
increased (E selectin)
E selectin correlates with the disease process UV rays decrease adhesion molecules! (PUVA therapy !!)
Now the Lymphocytes come out
of the venules (C5a)
CD4 or CD8 ?
CD4 in the dermis
CD8 migrate to the epidermis
Mechanism
T cell activation by super antigen
Release of huge quantity of cytokines
Transit time change
53 days
in Psoriasis
7 days
Histopathology
Early changes
Dilatation and congestion of vessels
Mild perivascular lymphocytic infiltration