Psoriasis Flashcards
GENETICS
What % of new cases of psoriasis are familial?
40%
What the the single Major Histocompatability Complex (MHC) locus is the strongest susceptibility locus for psoriasis?
(Strongest gene)
PSORS1
What environmental factors affect the course of Psoratic disease?
- Stress
- Infection
- Skin trauma
- Drugs
- Alcohol
What drugs are associated with worsening/developing psoriasis?
- Beta Blockers
- NSAIDs
- Lithium
- Anti-Malarials
What form of psoriasis has the strongest link with smoking?
Pustular psoriasis
What is the aetiology of psoriasis?
- T-lymphocytes & Dendritic cells produce cytokines
- These Cytokines stimulate keratinocytes
- Keratinocytes proliferate and increase inflammatory cells to the skin
- Epidermal Hyperplasia and inflammation occurs.
What are the peak decades of onset?
20-30yrs and 50-60yrs
What are the subtypes of Psoriasis?
- Thin Plaque Psoriasis
- Flexural Psoriasis
- Pustular Psoriasis
- Gutatte Psoriasis
What type of psoriasis is this?
Pustular Psoriasis
What type of psoriasis is this?
Guttate Psoriasis
What type of psoriasis is this?
Thin Plaque Psorasis
What is the commonest form of psorasis?
Plaque Psorasis
Where does plaque psoriasis most commonly appear?
- Scalp - 80%
- Elbows more than knees (75% vs 55%)
- Legs more than arms (75% vs 55%)
- Soles of the feet in 13%
If you notice psoriasis, what part of the body should you also examine.
The nails.
Look for Subungual Hyperkeratosis, Pitting, onycholysis.
What form of psoriasis is the 2nd most common form of psoriasis in adults & the most common in children?
Guttate Psoriasis
What is strongly linked to guttate psoriasis?
Streptococcal infection
What investigations should be done if you see guttate psorasis?
ASO Titres.
Check for sore throat.
What is the differential diagnosis for guttate psoriasis?
- Pityriasis rosea
- Secondary syphilis
- Rarely: pityriasis lichenoides chronica
What is the management of guttate psoriasis?
UV light.
Topical therapies don’t really work.
The plaques settle in a few weeks to a few months.
What type of psoriasis is this?
Flexural psoriasis
(AKA Inverse Psoriasis)
What type of psoriasis is this and how does it differ from cadidal nappy rash?
Napkin psoriasis
(There is clear demarcation here where as in candidal infection there are satellite lesions)
What type of psoriasis is this and what should you do as a GP?
Unstable psoriasis
- Refer as a Dermatological emergency
What type of psoriasis is this?
Erythrodermic psoriasis
- Differentials: Eczema, Drug Rection, Cutaneous T-Cell Lymphoma & Pityriasis rubra pilaris.
- Dermatological Emergency
- Biopsies are taken.
What type of psoriasis is this?
When does it develop?
How is it managed?
Palmar Pustular psoriasis
- Middle age
- Treat with topical therapies & Smoking cessation
- If these fail consider Acitretin.
What type of psoriasis is this?
Generalised Pustular Psoriasis
- Differntial Diagnosis: Acute Generalised Eruptive Pustulosis
- Pustular psoriasis may arise when patients stop or reduce oral steroids.
- Dermatological Emergency
What form of psoriasis is this?
How is it treated?
Acrodermatitis Continua of Hallopeau
Usually treated with methotrexate
What other areas of the body should you check in psoriasis?
- Scalp
- Anogenital area
- Fingers
- Joints
What percentage of patients have anogenital psoriatic lesions?
How is it treated?
30-40%
- Combination therapy with moderate strength steroids and antifungals. (Trimovate or Lotriderm) for intermittent periods.
What % of patients will have scalp psorasis?
80%
What is this form of psoriasis called?
Pityriasis Amianatacea
Large waxy adherent scales infiltrates and surrounds the base of a group of scalp hairs
5% of Psoriasis patients will have Psoriatic Arthritis.
What sort of joint disease can occur in psoriatic arthritis?
- Enthesesis - usually of the achilles tendon & thumb tendons.
- Plantar fasciitis.
- Monoarthropathies of large joints (Most common joint involvement)
- Less Common
- RA of the hands, sacroiliitis, enthesesis, arthritis mutilans
Describe the screening tool for arthritis in psoriasis?
PEST
Psoriasis Epidermiology Screening Tool
A score of >3 triggers a referral to rheumatology
How do you measure the severity of psoriatic disease?
- PASI (Psoriasis Area and Severity Index)
- DLQI (Dermatology Life Quality Index)
Severe = A PASI score of >=10 or a DLQI score of >10 or significant functional or psychological morbidity.
What is the mainstay of topical treatment in psoriasis?
Vitamin D Analogues (Dovonex)
How many grams of dovonex can you use per week before you are at risk of hypercalcaemia?
No more than 100g per week otherwise Hypercalcaemia can result.
What % of patients suffer from irritation from dovonex?
15%
What is a potential theoretical complication from tar based therapy?
Skin tumours
(Although all studies have no proven this)
Why is salicylic acid useful?
It helps to descale the plaques before vitamin D analogues or steroids are used.
How is dithranol used in psoriasis?
- Day treatment - because it stains skin, hair and clothing.
- Left on for 1-2 hours then washed off
- Can cause irritation.
- Good for large plaques.
What area of the body is coal tar useful for?
Scalp Psorasis
What is the best way to treat facial psoriasis?
Tacrolimus or Pimecrolimus + low dose steroids-tar combination
(Alphosyl HC in the UK)
What is the best way to treat genital psoriasis?
Steroid + Antifungal/Antibacterial cream
What is the best way to treat scalp psoriasis?
-
Lather & Massage the scalp for 5 minutes with antikeratolytic shampoo.
- Or try Cocois Co or SebCo overnight and Wash out with a keratolytic shampoo
- Topical steroid gel at night for 1 month and then switch to just weekends as maintenance therapy.
- Calcipotriol/steroid combiation gel to the scalp is useful as a regular therapy.
- Methotrexate can be used occasionally.
What is the best way to treat nail psoriasis?
- Keep nails short
- Topical calcipotriol/steroids can be applied to the nail bed
- Intralesional steroids in the nail matrix can help
- Methotrexate or biologic agents can be useful.
PUVA vs Narrow bank UVB therapy
Which is mroe effective?
Which has more side effects?
- PUVA is more effective
-
UV B has less side effects.
- No risk of cataracts
- No need to take Psoralen.
- No need for glasses like in PUVA
What is the recommended total dosage for both PUVA or narrow band UV B?
150 to 200 cumulative treatments
What should not be combined with PUVA?
Methotrexate or Cyclosporin
due to risk of carcinogenesis
UVB + other therapy is superseded by immunosuppressive therapies.
However, what is the INGRAM REGIMEN?
Dithranol in Lassar’s paste + Tar baths + UVB
What is Re-PUVA and why is it useful?
Retinoid PUVA
- Acitretin started before the UVA
- Benefits
- Lower doses of light are needed for effect.
- Lower incidence of skin cancer.
What form of psoriasis is methotrexate particularly useful for?
Why are low dose capsules used?
Psoriatic arthritis
- To avoid taking too much. (It has the highest number of drug errors)
What are some complications of methtrexate?
Liver and lung fibrosis
How long does it take to work?
6 weeks to show improvement
12 weeks to reach maximum effect.
What drugs can interact with methotrexate?
- Sulphonamides
- Trimethoprim
- NSAIDsa
What serological marker has replaced regular liver biopsies in patients?
Procollagen 3 assay
(The level reflects the degree of liver fibrosis from hepatic collagen synthesis)
How effective is methotrexate?
75% improvement in 90% of psoriatic patients.
How effective is ciclosporin and how does it work?
Improves chronic plaque psoriasis by 60-70% in 4 weeks.
It immunomodulates T-Cells.
How long should ciclopsorin be used and why?
12 months due to nephrotoxicity.
(But this often can be longer if people want clear skin and are willing to give up renal function for it)
How should ciclosporin be monitored?
Every 3 months for renal function and blood pressure.
What other systemic drugs can be used in psoriasis?
- Oral retinoids - combined with other drugs.
- Fumaric acid esters - can cause GI side effects or flushing
- Apremilast - - similar efficacy to methotrexate but doesn’t need regular blood tests.
- Mycophenolate Mofetil - not very useful.
- Hydroxyurea - can cause pancytopaenia, leukaemia and skin side effects.
- Biological therapies
