Psoriasis

Question 1

Define:

Answer 1

• A chronic inflammatory skin disease, which has characteristic lesions and may be complicated by arthritis

Question 2

Aetiology:

Answer 2

• UNKNOWN
Genetic, environmental factors and drugs are implicated - immune response defined by T cells in the dermis, initiating release of cytokines.

Histology: keratinocytes overproliferate so there is a thicker layer of keratin causing scales to come off the surface

Question 3

Risk factors for Guttate psoriasis:

Answer 3

type of psoriasis affecting teenagers and early 20s, triggered by streptococcal sore throat. Very small pink and scaly lesions

Question 4

Risk factors for palmoplantar psoriasis:

Answer 4

smoking, middle-aged women, autoimmune thyroid disease. Pustules on hands and feet.

Question 5

Risk factors for generalised pustular psoriasis:

Answer 5

hypoparathyroidism

Question 6

Epidemiology:

Answer 6

• Affects 1-2% of population

* Peak age of onset: 20 yrs

Question 7

Symptoms:

Answer 7

• Common locations: scalp, elbows, knees, buttocks, genital area, foot soles
• Itching and occasionally tender skin
• Pinpoint bleeding with removing scales (Auspitz phenomenon)

• Skin lesions may develop at sites of trauma/scars (Koebner phenomenon)

Question 8

Signs of discoid psoriasis:

Answer 8

symmetrical, well-demarcated erythematous plaques with silvery scales over extensor surfaces (knee, elbows, scalp, sacrum)

Question 9

Signs of flexural psoriasis:

Answer 9

less scaly plaques in axilla, groins, perianal and genital skin

Question 10

Signs of guttate psoriasis:

Answer 10

small drop-like lesions over trunk and limbs

Question 11

Signs of palmoplantar psoriasis:

Answer 11

erythematous plaques with pustules on palms and soles

Question 12

Signs of generalised pustular psoriasis:

Answer 12

• pustules distributed over limbs and torso

Question 13

What are signs in the nails:

Answer 13

o Pitting
o Onycholysis
o Subungual hyperkeratosis – build up of keratosis under nails

Question 14

What are signs of psoriatic arthritis:

Answer 14

o	Asymmetrical oligoarthritis 
o	Symmetrical polyarthritis 
o	Distal interphalangeal joint predominance 
o	Arthritis mutilans 
o	Psoriatic spondylitis

Question 15

Investigations:

Answer 15

• Most patients DO NOT need investigations
• Guttate psoriasis - anti-streptolysin-O titre, throat swab
• Flexural psoriasis - skin swabs to exclude candidiasis
• Nail clipping analysis for onychomycosis (fungal infection)
• Joint involvement analysed by checking for rheumatoid factor and radiographs