Psoriasis

Question 1

Define Psoriasis

Answer 1

Chronic inflammatory skin disease characterised by erythematous, circumscribed scaly papules, and plaques due to hyperproliferation of keratinocytes

Question 2

Aetiology of psoriasis

Answer 2

Unknown

• Genetic predisposition
• Immunology
• Infection (guttate following URTI e.g. strep. Pharyngitis)

May be triggered by stress, smoking, alcohol, drugs (antimarial, beta-blockers, lithium)

Question 3

Risk factors for psoriasis

Answer 3

FMHx or PMHx of psoriasis
Infection e.g. strep pharyngitis
Local trauma
Stress
Smoking
Light skin
Alcohol intake esp. beer
Greater BMI

Question 4

Symptoms of psoriasis

Answer 4

Itching or occasionally tender skin
Pinpoint bleeding with removing scales (Auspitz phenomenon)
Skin lesions occurring at the site of trauma/scars (Koebner phenomenon)
Often worse in the Winter months (responds well to Sun)

Question 5

Signs of plaque psoriasis on examination

Answer 5

Nail signs: onycholysis, pitting, subungal hyperkeratosis, “salmon patch

Symmetrical well-demarcated erythematous plaques
Purple, silvery plaques
Dry, flaky skin
Itchy/painful
Distributed on extensors/scalp

Question 6

What are the features of the following types of psoriasis: Pustular/palmo-plantar, guttate, flexural and erythrodermic

Answer 6

Pustular/palmo-plantar: Plaques/pustules on palms + plantars | Limbs + torso

Guttate: Raindrop plaques, small ~1cm | 2-weeks post-strep

Flexural: Found on the body folds e.g. axilla, groin, peri-anal area

Erythrodermic: Systemic body redness and inflammation | Often temp. dysregulation, electrolyte imbalance | Requires hospitalisation

Question 7

Describe psoriatic arthritis

Answer 7

Seronegative

1. Monoarthritis
2. Distal asymmetrical oligoarthritis (interphalyngeal joints)
3. Dactylitis
4. Rheumatoid arthritis-like (symmetrical polyarthritis)
5. Arthritis mutilans (telescoping)
6. Ankylosing spondylitis

Question 8

Investigations for psoriasis

Answer 8

Clinical Diagnosis

Skin Biopsy: intra-epidermal spongiform pustules and Munro neutrophilic microabscess within the stratum corneum (if diagnosis unsure)