SM 258: Papulosquamous Disorders Flashcards
What is Psoriasis?
An inflammatory skin disease that typically occurs in the elbows and knees, but can occur in any area of the body
What does Psoriasis look like?
Well defined, thick scaly rash with silvery scale on elbows and knees (any site is possible though)
Is Psoriasis well defined?
Yes - well defined islands with salmon pink color outlining the rash due to increased vasculature
What is Onycholoysis?
Yellow discoloration seen by lifting of the nail plate from the bed in Psoriasis
How does Psoriasis affect the nails?
Psoriasis effects both the nail itself and the nail bed of skin underneat the nail, causing pitting and onycholoysis
What is the histological correlate for the bright led appearance of the Psoriasis rash?
Blood vessels form in effected areas, which show up as white spots on histology
What does Psoriasis look like on histology?
An elongated, thickened epidermis is seen due to rapid proliferation of Keratinocytes
This causes the scales we see on skin
Is Psoriasis temporary?
No, it’s a chronic condition that can develop at any age of life
Is there a genetic basis to Psoriasis?
There is a genetic factor since it runs in families, but not always
What causes the hyperprolfieration in Psoriasis?
Psoriasis is an immune mediated condition, with the hyperproliferation of Keratinocytes being driven by a complex cascadde of immune mediators
What type of immune cell drives Psoriasis, and with what signalling molecules?
Th1/Th17 T cells, which overexpress TNFalpha, IL-17, IL-12
What type of diseases is overexpression of TNFalpha related to?
Skin: Psoriasis
Joints: RA and Psoriatic Arthritis
GI: Crohn’s Disease/UC
What can trigger Psoriasis?
Streptococci, Trauma to skin, Beta Blockers and Lithium
What is Psoriatic Arthritis?
An inflammatory immune mediated arthritis that can lead to disability
Inflammatory stiffness (improves after moving) and Dactylitis
Driven b TNFalpha overactivation of Osteoclasts
What are the treatments for Psoriasis localized disease?
Potent topical steroids like Clobetasol and Triamcinolone
Do topical steroids work forever?
No - they work for a few weeks but Psoriasis comes back later
What targeted therapies exist for Psoriasis?
Biologics including: TNFalpha blockers, IL-23 blockers (Ustekinumab), and IL-17 blockers (Secukinumab)
What is Seborrheic Dermatitis?
Redness and thin yellow flaking around the nose, eyebrows, ears, hairline, and scalp
How does Seborrheic Dermatitis differ from Psoriasis?
Asymptomatic: not itchy, and more flakey
What may cause Seborrheic Dermatitis?
Pityrosporum Ovale
What is the treatment for Seborrheic Dermatitis?
Antifungal creams or mild topical steroids
What is Pityriasis Rosea?
Oval salmon colored thin macules or patches with thin scale that mostly effect the trunk, often beginning after a larger initial patch
How does Pityriasis Rosea differ from Psoriasis?
No scale, smaller rashes, and Pityriasis Rosea resolves acutely within 3-8 weeks
What is the “Christmas Tree” pattern?
A pattern of small rashes on the back that look like a Christmas tree, common in Pityriasis Rosea
