Wk 30 - Dermatology OTC (Psoriasis) Flashcards
How does psoriasis occur?
- Stimulation of cutaneous vasculature -> new blood vessel formation in psoriatic plaques
- Dec epidermal turnover time (4 days)
What are the clinical features of psoriasis?
- Red, scaly, sharply demarcated plaque
- Common sites: extensor surfaces of elbows, knees, sacrum + scalp
- Scales scrape off revealing tiny bleeding points
- Pruritus (itching)
What are precipitating factors of psoriasis?
- Trauma
- Infection
- Hormones
- Sunlight
- Smoking + alcohol
- Bblockers, lithium + antimalarials
What is chronic plaque psoriasis?
- Flexural psoriasis = little/no scale bc friction against other skin
- Symmetrical + crack + bleed
What is guttate psoriasis?
- Affects children + young adults
- Occur 1st presentation or exacerbation of chronic plaque
- Follows strep throat
- Small, red macules, scaly then clear after few months
What are the medical emergency psoriasis?
- Erythrodermic: all skin surface, precipitated by infection, tar, drugs or w/drawal of corticosteroids
- Pustular: w/ fever + toxicity, genitals, fingers + flexures
What is psoriatic arthritis?
- Affects hands + feet
- Swollen, inflamed, painful joints
- Refer to rheumatologist
What is nail psoriasis?
Pitting of nails, discolouration, hyperproliferation of nail bed, oncholysis
How is psoriasis assessed?
- Psoriasis area severity index: from 0-4, redness, thickness + scaliness
- Physician global assessment: Clear, almost clear, mild, moderate, severe, lesion erythema, induration + scale
What is the first line treatment for psoriasis?
- Emollient: soften blacks + improves abs
- Topical corticosteroids
- Vit D analogues
- Dithranol
- Tar
What is the second line treatment for psoriasis?
- Phototherapies
- MXT, ciclosporin, acitretin
What is the third line treatment for psoriasis?
Biologics:
- Adalimumab
- Etanercept
- Infliximab
- Ustekinumab
What are the BAD guidelines for management of psoriasis w/ topical steroids?
- Don’t use more than 4 wks w/o review
- Don’t use potent steroids >7 days
- Review 3 months
- No more than 100g mod/high potency per month
- Rotate topical steroids w/ alt
Which vitamin D analogues are used?
- Calcipotriol
- Tacalcitol
- Calcitriol
What is the MOA of vitamin D analogues?
- Inhibit keratinocyte differentiation + proliferation
- Used in mild/mod chronic plaque psoriasis
- Clears in 6-8 wks
What are the counselling points of Vitamin D analogues?
- Skin irritation = inc redness/dryness + stinging
- Calcipotriol: not for face/flexures
- Calcitriol: face/flexures
- Finger tip unit, apply thickly
- Max dose to avoid hypercalcaemia: calcip 100g, calcit 210g, taca 70g
What is tazarotene?
- Activated retinoids
-Normalises keratinocyte differentiation, anti-proliferation
-teratogenic
What is the problem w/ coal tar?
Smells unpleasant + stains clothing
What is dithranol?
- Irritant to skin
- Temp staining
- Response w/in 3 wks
- Not for: multiple small plaques or flexural psoriasis
What is phototherapy?
- Modulate expression of cellular adhesion molecules + induce T-cell apoptosis
- 3x/wk
- CI: photosensitising med/photosensitive disease
What is phototherapy - PUVA?
- Combine 8-MOP + UVA
- MOP tab: 1-2 hrs before radiation
- Photosensitive til psoralen cleared tf resunscreen
- 2x/wk for 10 wks
- Cause nausea, inc risk of skin cancer + photoaging
How does cyclosporine work in psoriasis?
- Blocks intracellular component of T-cell activation
- Inhibit calcineurin phosphatase, inhibits nuclear factor of activated T-cells
- Clear in 6-8 wks
How does oral retinoid work in psoriasis?
- Bind to nuclear receptor + regulate gene transcription
- Induce keratinocyte differentiation + red epidermal hyperplasia
What are things to be aware of when giving oral retinoid?
- LFTs + lipid start of therapy + every 2-4 wks for 2 months then 3 months
- CI: MXT, Tetracycline, children, child bearing women (teratogenic)
- Cause: dryness of mucous membrane, skin + conjunctiva
- Px female in PPP valid 7 days + 30 day treatment
What are the counselling points for psoriasis?
- Can’t be cured
- Not infectious
- Doesn’t develop into skin cancer
- Can’t spread to other areas
