Psoriasis

Question 1

What is the pathogenesis of psoriasis?

Answer 1

It is hyperproliefteration of the epidermis where the plaques are. There is also dilation of the blood vessels in the dermis and infiltration of inflammatory cells
Main triggers are stress and infections

Question 2

What are the types of psoriasis?

Answer 2

Chronic plaque psoriasis - well defined plaques on extensor surfaces
Flexural psoriasis - plaques in moist flexural areas e.g. axillae, groins
Guttate psoriasis - large numbers of small plaques on trunk and arms usually after strep infection in young
Pustular psoriasis - pustular plaques affecting palms and soles
Generalised (erythrodermic) psoriasis - may cause severe systemic upset - medical emergency requiring hospital referral

Question 3

What is the management of psoriasis?

Answer 3

Education is vital - need to control not cure
Topical treatment - for plaque psoriasis - use topical corticosteroid (betnovate) and a vit D preperation to reduce cell division
Phototherapy - narrowband UVB used for plaque psoriasis
Systemic treatments:
non biologics - methotrexate/ciclosporin
Biological drugs - inhibit T cell activation and function e.g. infliximab

Question 4

What are the locations of plaques in chronic plaque psoriasis?

Answer 4

Symetrical and well defined
On the extensor surfaces of elbows and knees
Scalp and sacrum

Question 5

What differetiates flexural psoriasis from infection on the presentation?

Answer 5

Flexural psoriasis tends to be bilateral whereas fungal infections are more likely to be unilateral

Question 6

What are the locations and characteristics of flexural psoriasis?

Answer 6

It is present in the axillae, umbillicus, groins and submammary areas
It is often less scaly so mistaken for fungal infection

Question 7

What is the typical history for guttate psoriasis?

Answer 7

This is a raindrop type rash of plaques that is all over the torso, often seen in the young following a strep infection and lasts 3-4 months

Question 8

What is pustular psoriasis also known as?

Answer 8

Plantopalmar psoriasis because of where it affects

Question 9

What can cause generalised (erythrodermic) psoriasis or generalised pustular psoriasis?

Answer 9

Rapid withdrawl of steroids

Never used oral steroids in psoriasis because of this

Question 10

What nail changes are seen in psoriasis?

Answer 10

Pitting
Onycholysis (seperation of nail bed)
Thickening and subungual hyperkeratosis (very overgrown nails)

Question 11

What are the topical treatments for psoriasis and what are the disadvantages of each?

Answer 11

Calcipotriol - vitamin D - Irriation especially on face
Tar - smelly
Betnovate - can cause atrophy
Dithranol - stains clothes