Skin: Psoriasis, Atopic Dermatitis

Question 1

Psoriasis

• epidemiology
• etiology, triggers

Answer 1

White, 20s and 60s
HLA B13-17 - P
HLA B27 - PA

Abnormal T cell activity => overproduction of keratin and angiogenesis

Worsened by trauma, stress, strep infection
Improved by sun

Question 2

Psoriasis

-presentation and types

Answer 2

Plaque - most common

• demarcated red, scaly silvery patches
• extensors, sacrum, scalp
• pinpoint bleeding when picked

Guttate

• transient psoriatic rash triggered by strep infection 2-4wks before
• red, teardrop lesions on trunk, limbs

Flexural
-smooth skin

Pustular
-palms and sores

Question 3

Psoriasis

• nail, joint presentation
• complications

Answer 3

Nail pitting, onycholysis
Psoriatic arthritis + seronegative conditions

Increased risk of

• metabolic syndromes
• CVD, VTE
• psych distress

Question 4

Psoriasis

-diagnosis, investigations

Answer 4

Clinical diagnosis based on appearance

-psoriatic arthritis investigations if suspected

Question 5

Psoriasis

-management

Answer 5

Initial - topical VitD/CS
Escalate to phototherapy
Escalate to methotrexate, biologics

Question 6

Atopic dermatitis

• epidemiology, etiology
• pathophsyiology

Answer 6

1-5 year olds
Associated with atopic march (AD, asthma, rhinitis)

Defective skin barrier => immune response to innocuous triggers
-allergens, irritants, stress

Question 7

Atopic dermatitis

-presentation

Answer 7

Eczema on flexor surfaces, face, neck
-general dryness
-impetignization - infection of eczema
Chronic => lichenification

Question 8

Atopic dermatitis

-management

Answer 8

Initial - topical CS + emollients

• calcineurin inh if not enough
• phototherapy if not enough
• metotrexate, biologics if not enough

Question 9

Acne

• epidemiology, pathophysiology, causative organisms
• presentation

Answer 9

Common in teens
Multifactorial pathophysiology
-Keratin plugs obstruct pilosebaceous follicles => comedones, inflammation, pustules
-Propionibacterium acnes

Face, neck, upper trunk

Question 10

Acne

-management

Answer 10

Lifestyle

• avoid overcleaning skin
• use skin neutral pH cleaning protuct

Mild/moderate - combination of topical antiseptic, retinoid, ABx
-benzoyl peroxide, clindamycin, tretinoin

Moderate/severe - any mild treatment or

• azelaic acid + lymecycline
• COCP