Psoriasis

Question 1

What drugs can trigger psoriasis?

Answer 1

1. Antimalarials
2. Lithium
3. B blockers
4. Indomethacin
5. Mepacrine
6. ACE inhibitors
7. Alcohol
8. Topical drugs
9. Overuse and sudden withdrawal of some oral corticosteroids

Question 2

What is Kobners phenomenon?

Answer 2

1. Traumatised skin resulting in a psoriatic event at the site of injury
2. Cytokines released —> activate T cells
3. T cells —> more cytokines, keratinocytes and inflammation

Question 3

What is plaque psoriasis?

Answer 3

Start as small papules that then grow and unite to form a plaque

Question 4

What does plaque psoriasis look like?

Answer 4

Classic silvery white scaly appearance

Question 5

What are the major biological abnormalities of plaque psoriasis?

Answer 5

1. Hyperproliferation of the epidermis
2. Abnormal differentiation of keratinocytes
3. Infiltration of the dermis and epidermis with activated T lymphocytes and neutrophils
4. Stimulation of the cutaneous vasculature

Question 6

What does guttate psoriasis like?

Answer 6

Initially start of as pink papules that become scaly, arises rapidly and responds well to treatment

Question 7

When does guttate psoriasis usually occur?

Answer 7

After a streptococcal throat infection - possibly superantigen stimulation of the IS

Question 8

What is erythrodermic psoriasis?

Answer 8

A severe variant that is widespread with massive protein loss, problems maintaining core body temperature and excessive fluid losses - requires aggressive treatment in hospital

Question 9

What are the complications of erythrodermic psoriasis?

Answer 9

Pustulosis, arthropathy, staphylococcal skin infection and growth retardation

Question 10

What is pustular psoriasis?

Answer 10

A severe form that causes superficial pustulation of the lesions often on the palms and soles

May be widespread - associated with fever and malaise, fluid and electrolyte disturbances and infection

High relapse rate - can be fatal - hospitalised

Question 11

What are the main changes to nails in nail psoriasis?

Answer 11

1. Pitting
2. Oncholysis - selecting nail from nail bed
3. Accumulation of subungual debris
4. Colour changes

More often finger than toe nails

Question 12

What is psoriatic arthritis?

Answer 12

In the peripheral interphalangael joints - RF not elevated - difficult to distinguish from rheumatoid arthritis

Associated with cutaneous changes - nail and scalp

Question 13

What is inverse/flexural psoriasis?

Answer 13

Smooth inflamed lesions mostly in creases or folds - minimal or absent scaling

Perinanal skin in children and beneath breast in women

Question 14

What are emollients?

Answer 14

Bath oils, soap substitutes and skin creams that moisturise, lubricate and soothe dry flaky skin by forming an occlusive film

To moisturise - apply liberally all over body tid

Psoriatic plaque - pretreatment

Contact dermatitis and foliculitis - ADR’s

Question 15

Where is dithranol from?

Answer 15

Brazilian tree - Andira araroba

Question 16

What does dithranol do?

Answer 16

1. Slows cell proliferation
2. Decrease inflammation

Very effective with no systemic S/E

Question 17

How do you use dithranol?

Answer 17

1. 0.05 - 0.1% starting concentration applied each night at bedtime
2. Rinse off each morning - coat skin with emollient
3. Increase dose after a few days
4. Little increase efficacy after 5%

Question 18

What are the problems with dithranol?

Answer 18

1. Staining
2. Inflammation and irritation of non psoriatic skin
3. Short treatment
   - 0.1% for 5-20 mins
   - 1% over 5 mins
4. Not as effective as calcipotriol in clearing lesions

Question 19

What is coal tar?

Answer 19

White soft or yellow soft paraffin base available in lotions, gels or shampoos

5% most effective

Question 20

What are the problems with coal tar?

Answer 20

1. Smelly, messy and stains clothing
2. Irritation - can cause contact dermatitis
3. Phototoxic response
4. Don’t apply over a large area - use on well separated small lesions

Question 21

How are corticosteroids applied?

Answer 21

Applied directly to lesion - goal is to increase time of remission

May make a lesion disappear but may return after discontinuation - taper strength

Question 22

What do you use for plaque psoriasis?

Answer 22

High potency topical steroid bd until control

Question 23

What are the S/E’s of corticosteroids?

Answer 23

1. Skin atrophy - thinning of skin after 3-14 days
2. Increase in fine hair growth
3. Hypopigmentation
4. Allergic contact dermatitis
5. Systemic absorption - adrenal suppression

Question 24

What is an example of a vitamin D analogue?

Answer 24

Calcipotriol

• 50 micrograms/gram ointment
• 50 micrograms/gram scalp lotion
  Max weekly cumulative dose = 5mg ie. 100g or 100ml
• use once or twice a day
• notice effect week 2
• max effect - weeks 6 to 8
• flare up if used intermittently

Question 25

What are the adverse reactions of calcipotriol?

Answer 25

1. Skin irritation - don’t use on face or flexural areas 2. Peripheral ring of scales around treated lesions 3. Rare - hypercalcameia

Question 26

How do retinoids work?

Answer 26

Tazarotene 1. Topically active retinoid 2. Normalise keratinocyte differentiation 3. Anti-proliferative and anti-inflammatory effects 4. Moderately effective 5. Limited by skin irritation and increased photosensitivity 6. Adequate contraception required in women of child bearing age

Question 27

How does phototherapy work?

Answer 27

1. Phototherapy = UVB radiation 2. Photo chemotherapy = light plus drugs 3. PUVA therapy (psoralen and UVA) 4. Take 2 hours before therapy 5. Peak effect - 48 to 72 hours post therapy 6. Shield eyes and skin from sun for 6 hours

Question 28

What drugs are used for systemic therapy?

Answer 28

1. Retinoids 2. Cyclosporin 3. Methotrexate 4. Tacrolimus 5. Psoralens 6. Biologic therapy agents

Question 29

What are the indications for systemic therapy?

Answer 29

1. Failure of adequate topical trials 2. Repeated hospital admission 3. >10% of body affected 4. Extensive chronic plaque psoriasis in elderly or infirim 5. Widespread pustular or erythrodermic psoriasis

Question 30

What are retinoids used for systemic therapy?

Answer 30

1. They are vitamin A derivatives 2. Eg. Acitretin 3. Most effective for pustular and erythrodermic psoriasis 4. Limit to severe forms 5. Initial dose —> maintenance dose 6. Teratogenic 7. Avoid in severe liver and kidney disease

Question 31

What is systemic methotrexate used for?

Answer 31

1. Used in patients unresponsive to topical therapy 2. Can be used in severe pustular or erythroderma, arthritis and plaque involving more than 20% 3. Folic acid antagonist 4. Given weekly - caution 5. Monitor blood, liver and kidney function

Question 32

What is systemic ciclosporin used for?

Answer 32

1. Resistant disease 2. Immunosuppressant 3. Use lowest possible dose 4. Monitor BP and kidney function 5. Never exceed 5mg/kg/day 6. 90% remission in 7-10 weeks 7. Relapse 2-4 months post treatment 8. Tacrolimus - similar to ciclosporin

Question 33

How do biological therapy agents work?

Answer 33

1. Block T cell activation 2. Inhibit T cell proliferation 3. Inhibit T cell destruction 4. Block effector cytokines

Question 34

What biological agents are used to treat psoriasis?

Answer 34

1. Etanercept - 12 weeks 2. Infliximab - 10 weeks 3. Adalimumab - 16 weeks 4. Ustekinumab - 16 weeks Consider changing to an alt biological drug in adults if the psoriasis doesn’t respond adequately to a first biological drug ( see above for time for change)

Question 35

What are the risks with biologic agents?

Answer 35

1. Risk of immunosuppressive not known 2. Increased risk of infection and reactivation of TB 3. S/E’s include influenza like symptoms, leucocytosis, arthralgia, exacerbation of psoriasis or development of variant forms 4. 1/3 of patients respond rapidly others slowly or not at all 5. Control not cure

Question 36

How should topical corticosteroids be used?

Answer 36

Sparingly and gradually withdrawn