Psoriasis

Question 1

What is psoriasis?

Answer 1

A chronic, relapsing-remitting autoimmune disorder, characterised by patchy inflammation of the skin. [NHS]

Question 2

Describe the pathophysiology of psoriasis.

Answer 2

1. Inflammation in the dermis - T cells and other WBCs migrate to the epidermis and release cytokines there.
2. Premature maturation of keratinocytes
3. Excessive epidermal growth
   [wiki]

Question 3

Describe the epidemiology of psoriasis.

Answer 3

Onset in 20s
Unusual in <6 year olds
M=F
Wide variation in severity
80% is plaque psoriasis.
[NHS]

Question 4

What causes psoriasis?

Answer 4

Genetics - PSORS 1-9 susceptibility genes lead to inflammation.
Environmental triggers - change in weather, stress, chronic infections, trauma

Question 5

Describe the distribution of psoriasis lesions.

Answer 5

Well-defined disc-shaped plaques. Most commonly extensor surfaces - knees, elbows; scalp and lower back. Can be anywhere. [nhs]

Question 6

What is the most common form of psoriasis?

Answer 6

Psoriasis vulgaris/ plaque psoriasis. (80%) [nhs]

Question 7

Describe the appearance of psoriasis lesions.

Answer 7

Dry, red, covered in silver scales.

Question 8

Give a symptom of psoriasis.

Answer 8

Itchy, sore lesions

Relapsing/remitting course.

Question 9

What nail changes may occur in 50% of people with psoriasis?

Answer 9

Dents/pits
Discolouration
abnormal growth
Onycholysis = Loosening/separation of nail from nailbed.

Question 10

What may cause red glazed plaques at the underarm and groin areas in a person aged 50?

Answer 10

Flexural (inverse) psoriasis. Can be exacerbated by friction and sweating.

Question 11

What might cause small lesions over the chest and arms in a 16-year-old, and what infections may precede it?

Answer 11

Guttate (eruptive) psoriasis - small ‘drop-like’ (guttate) lesions. Often follows streptococcal throat infections. (raindrops in the gutter)

Question 12

Describe the management of guttate psoriasis.

Answer 12

Mild corticosteroids, usually clears up after treatment.

Question 13

What could cause pustules on the palms and soles?

Answer 13

Palmoplantar pustular psoriasis. Pustules develop into brown scaly spots which then peel off.

Question 14

Describe the management of mild plaque psoriasis.

Answer 14

Emollients
Topical vitamin D analogues, eg calcitriol - slow production of skin cells and are anti-inflammatory.
Topical corticosteroids eg betamethasone dipropionate
Topical retinoids eg tazarotene

Question 15

Describe the management of moderate plaque psoriasis.

Answer 15

Phototherapy - natural and artificial light used to treat psoriasis. (nb: NOT a sunbed)

Question 16

Describe the management of severe plaque psoriasis.

Answer 16

Oral methotrexate
Ciclosporin
Oral retinoids eg acitretin - induces keratinocyte differentiation, slows proliferation.
If systemic tx fails, try biologics eg Infliximab

Question 17

Ciclosporin - class, mechanism?

Answer 17

Calcineurin inhibitor/ DMARD. Binds to cyclophilin produced by T lymphocytes, forming a complex which inhibits calcineurin, so less IL-2 is released, causing immunosuppression. [wiki]

Question 18

Give 3 side-effects of ciclosporin and why they occur.

Answer 18

Increased infections due to immunosuppression
Feeling ‘shaky’
Hypertension - vasoconstriction in the kidneys, increases sodium reabsorption.
Loss of appetite
Muscle cramps/ pain
Increased GFR -> retention of uric acid -> Gout

Question 19

Give 3 interactions of ciclosporin and what happens.

Answer 19

Immunisations - already immunocompromised
Clarythromycin, erythromycin - increases ciclosporin concentration
Atorvastatin - increases atorvastatin exposure -> liver damage, rhabdomyolysis.
Grapefruit juice - decreases ciclosporin exposure

Question 20

Give 3 contraindications of ciclosporin

Answer 20

Cancer
Alcohol intake
Kidney malfunctions/ transplantation -> risk of gout
Hypertension

Question 21

What can be used as an alternative to ciclosporin in people who have had a kidney transplant?

Answer 21

Azothiaprine. Does not carry risk of gout.