dermatology PT 2 Flashcards
what is psoriasis?
Chronic, inflammatory skin disease
what abnormalities does psoriasis cause?
– Infiltration of the dermis and epidermis with activated Tlymphocytes & neutrophils
– Stimulation of the cutaneous vasculature leading to new
blood vessel formation in the psoriatic plaques
– Decreased epidermal turnover time (from 28 to ~4 days)-
overproduction of skin cells
what causes psoriasis?
- Cause unknown, genetic aspect may
predispose some people to the condition
what are the key clinical features of psoriasis?
- A typical psoriatic lesion is red, scaly,
sharply demarcated plaque - May be any size and affect any part of the body
- Most common sites are extensor surfaces of elbows and knees, sacrum and scalp
- Hands and feet frequently involved
- Scale is easily scraped off revealing tiny bleeding points
- Pruritus
- Relapsing and remitting condition
- Often impact on QoL with phsycological/social
disability
what are the precipitating factors for psoriasis?
- Many people with psoriasis can pinpoint a trigger event or experience that preceded the onset of psoriasis
- Trauma
- Infection
- Hormones
- Sunlight- usually improves psoriasis but 10% worsen
- Medication e.g. beta blockers, lithium, antimalarials
- Alcohol
- Smoking
- Profound psychological stress
what is chronic plaque psoriasis?
Psoriasis ‘plaques’ are formed by the build up of skin cells
* Red (increased blood supply to area), itchy, sore, white/silvery scales
what is the difference with flexural psoriasis?
may have little or no scale due to friction against other skin in these areas e.g. submammary, axillary, ano-genital
folds
what is guttate psoriasis? who does it affect? when does it happen?
- Usually affects children and young adults
- Can occur as first presentation of psoriasis or as an exacerbation of chronic plaque psoriasis
- Commonly follows a streptococcal throat infection
- Usually self-limiting
- Widespread small, red macules
which become scaly but clear within a few months
what is erythrodermic psoriasis?
Erythromdermic v. rare - a generalised redness of the skin involving all, or nearly all (usually stated as at least 90%) of the skin’s surface.
when does erythrodermic psoriasis occur?
Usually occurs in two contexts:
* In the setting of known, progressively worsening chronic plaque psoriasis.
* It may be precipitated by infection, tar, drugs, or withdrawal of corticosteroids
what is generalised pustular psoriasis?
- A v. rare generalised eruptive form of psoriasis accompanied by fever and toxicity
what does generalised pustular psoriasis look like?
Acute erythema is seen with a rapid spread of
multiple sterile pustules over the body,
concentrated in the flexures, genital regions
and fingertips.
how common is psoriatic arthritis?
- Affects up to 1 in 5 people with psoriasis
how does psoriatic arthritis affect a patient? how is it treated?
- Most commonly affects hands and feet
- Swollen, inflamed, painful joints
- Usually involves referral to rheumatologist
- NSAIDs/ Steroids/ DMARDs/ Biologics may be
required
what happens in nail psoriasis?
- Pitting of nails, discolouration (‘oil spots’ ‘salmon patches’), hyperproliferation of nail bed, oncholysis
what/how would you assess the condition?
assess disease severity, impact of disease on
physical, psychosocial, social wellbeing, psoriatic arthritis, co-morbidities
what/how would you assess the condition?
assess disease severity, impact of disease on
physical, psychosocial, social wellbeing, psoriatic arthritis, co-morbidities
where is psoriasis usually managed?
Usually managed in primary care, with specialist referral being needed at
some point for up to 60% of people
what tool do you use to assess the severity of the condition?
PASI = psoriasis area severity index
how does PASI work?
- Scoring procedure often used to evaluate psoriasis clinically and to
measure outcomes in clinical trials. - Scores severity of lesions (from 0-4) in terms of redness, thickness and
scaliness, and the score is weighted according to the area affected. - Following treatment or in clinical trials, endpoints such as PASI 75 (a 75%
reduction in disease activity) are used to measure progress of treatment.
what does the PGA score indicate?
Physician Global Assessment
* A scoring system is based on response to treatment as measured by lesion erythema, induration, and scale
* Score assignments that range from clear, almost clear, mild, moderate, to severe
how do emollients work in psoriasis?
- Soften plaques, reduce itching and redness, improve absorption of topical treatments. May have anti-proliferative effect on psoriasis
- Different products may be needed for different areas
what are the first line treatment options for psoriasis?
- topical corticosteroids
- vitamin D
analogues - dithranol
- tar preparations
what are the first line treatment options for psoriasis?
- topical corticosteroids
- vitamin D
analogues - dithranol
- tar preparations
what are the second line treatment options?
- phototherapies
- systemic non-biologic therapies:
- methotrexate,
- ciclosporin,
- acitretin
what are the 3rd line treatment options?
- systemic biologic therapies:
- adalimumab
- etanercept
- Infliximab
- ustekinumab
when may salicylic acid be used?
may be used to remove scale before potent steroid application if initial treatment for 4 weeks is not satisfactory.
what guidance is there around corticosteroids?
– Useful in acutely inflamed plaques and on face/ flexures
– Not as effective on chronic scaly plaques
– Risk of rebound flare
* BAD guidelines for management of psoriasis with topical steroids
– Do not use regularly for more than 4 weeks without review…..patient may
need follow up appointment
– Do not use potent steroids regularly for more than 7 days
– Review every 3 months
– No more than 100g of a moderately potent or higher potency preparation
should be applied per month
– Attempt to rotate topical steroids with alternative non-steroid preparations
what are the vitamin D analogues available?
- Calcipotriol, tacalcitol, calcitriol
how long do vitamin D analogues take to work?
Useful in mild-moderate chronic plaque psoriasis, can clear psoriasis in 6-8 weeks
what are vitamin D analogues MOA?
– Inhibit keratinocyte differentiation and proliferation
– May have some anti-inflammatory activity
what are the benefits of VIT d analogues?
- Don’t smell/stain like older treatments (tar/dithranol)
- May be as effective as potent steroid , but with longer duration of remission after treatment has stopped
what side effects may vit D analogues have?
- Can cause skin irritation, resulting in transient increased redness/dryness and stinging/burning
– Calcipotriol should not be used on face/flexures
– Calcitriol OK, less irritant
how should vit D analogues be applied?
Adequate quantities should be used – 0.5g (a fingertip unit) for 10cm2 skin (one medium sized adult palm)
* Apply thickly (unlike steroids)
* Maximum weekly dose to avoid risk of hypercalcaemia
– Calcipotriol 100g, calcitriol 210g, tacalcitol 70g
what is tazarotene? how does it work?
- Topically active retinoid (vitamin A derivative)
- Mechanism of action
– Normalises keratinocyte differentiation
– antiproliferative and anti-inflammatory effects
why is tazarotene generally avoided?
- Use is limited by skin irritation and increased photosensitivity
- Teratogenic
what is the thought MOA o coal tar?
thought to be keratolytic with some anti-inflammatory and antiproliferative effects
what are the disadvantages of coal tar?
- Stains clothing
- Smells unpleasant
- Less effective than vitamin D preparation
Theoretical risk of carcinogenicity- no epidemiological evidence
what are the disadvantages of dithranol?
- Profoundly irritant to skin, causing inflammation and blistering
- Causes temporary staining of skin, and permanent staining of clothing and bathroom fittings
what is used to prevent spreading of dithranol to uninvolved skin areas?
lassar’s paste
how long does it take dithranol to work?
- Response to treatment can be expected within 3 weeks
what is SCDT?
- Short-contact dithranol treatment (SCDT)
– Application of up to 8% for between 15-30
minutes with or without UVB
– Suitable for home use
what is phototherapy and how does it work?
- UVB (responsible for sunburn) or PUVA therapy
- Thought to modulate expression of cellular adhesion molecules and induce T-cell apoptosis
- UVB Dose adjusted to match the patient’s skin type
– Usually 80% of minimum erythemogenic dose (MED)
3 weeks till cleard
what is PUVA?
- Combination of 8-methoxypsoralen (MOP) and UVA
how is UVA dose determined ?
by assessment of skin type
– MOP Tablets: 1-2 hours before irradiation
– Topical (lotion, paint, bath solution)- applied immediately before irradiation
– unlicensed
when is the patient not photosensitive?
- Patient remains photosensitive until psoralen cleared from body, therefore advise re sunscreen
how does methotrexate work?
– Interferes with DNA synthesis by preventing the formation of tetrahydrofolate
– Monitoring in the same way as other indications, purple book etc
how does ciclosporin work?
– Blocks intracellular components of T-cell activation through a series of interactions
– Results in inhibition of calcineurin phosphatase…….inhibits nuclear factor of activated T-cells
– Doses 2.5-5mg/kg can clear psoriasis in 6-8 weeks
– Sometimes used for maintenance but risks vs benefits.
– Drug interactions, monitoring and side-effects
how does the oral retinoid acitretin work?
- Bind to nuclear receptors and regulate gene
transcription - Induce keratinocyte differentiation and reduce epidermal hyperplasia
what has to be monitored with acitretin?
hepatotoxic so:
* LFTs and lipid profile at start of therapy, then every 2-4 weeks for 2
months then 3 monthly
who should oral retaonids not be given in?
Contraindications/cautions: concomitant methotrexate or tetracycline,
avoid in children
if a woman is of child bearing age what must she agree to with oral retinoids? how long does the prescription last?
Oral retinoids contra-indicated in women of child-bearing potential unless used in conjunction with a pregnancy prevention programme (PPP)
– Prescriptions for female patients in a PPP are only valid for 7 days and are limited to 30 days of treatment
how do biologics work in psoriasis?
- Monoclonal antibodies and fusion proteins
- Interfere with T-cell function
what are the general psoriasis counselling points?
- Psoriasis cannot be cured, but can be
controlled - Is not infectious
- Does not develop into skin cancer
- Cannot be spread to other areas of skin
through application of topical treatments
