Inflammatory
dermatoses |
Psoriasis
• prevalence estimated at 1-3% of the population
• positive family history in 30% of patients; inheritance is
"multifactorial"
• can develop any time during life
Pathogenesis
• basic defect in psoriasis is unknown
• psoriasis is a chronic immunologic disease of the skin characterized by
profound
cutaneous inflammation and epidermal hyperproliferation
• in psoriasis, it takes 3-4 days for a keratinocyte to transit from the
basal layer to the
surface where it is shed; this process takes » 28 days in normal skin
• one of the current leading theories is that the epidermal
hyperproliferation is secondary
to the cutaneous inflammation
• key role for T
• psoriasis is known to be aggravated by environmental factors:
- Koebner phenomenon
- infections:
- group A streptococcal infections can precipitate acute guttate
psoriasis
- psoriasis may be precipitated or worsened by HIV infection
- stress: can be difficult to distinguish between stress that worsens
psoriasis from psoriasis that causes stress
- alcohol and drugs:
- prednisone: can cause severe flare up of psoriasis after
discontinuation
- beta blockers, lithium (plus many others)
- any cutaneous drug eruption can Koebnerize psoriasis
Psoriasis
- Clinical:
- key features
- sites of predilection
- variants of
psoriasis
- guttate psoriasis
- inverse
psoriasis
- pustular
psoriasis
-
erythrodermic psoriasis
- Pathogenesis:
-
koebner phenomenon
- Complications
- Treatment
- Micropathology
