Psoriasis Flashcards by M Njm

Psoriasis prevalence

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patients with psoriasis are at increased risk of

arthritis and cardiovascular disease.

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Pathophysiology psoriasis immunology?

Abnormal T cell activity stimulates keratinocyte proliferation.
There is increasing evidence this may be mediated by a novel group of T helper cells producing IL-17, designated Th17. These cells seem to be a third T-effector cell subset in addition to Th1 and Th2

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Pathophysiology psoriasis genetics

associated HLA-B13, -B17, and -Cw6. Strong concordance (70%) in identical twins

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Psoriasis is multifactorial and not fully understood

true

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Environmental factors for psoriasis?

it is recognised that psoriasis may be worsened (e.g. Skin trauma, stress), triggered (e.g. Streptococcal infection) or improved (e.g. Sunlight) by environmental factors

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Recognised subtypes of psoriasis

plaque psoriasis
flexural psoriasis
guttate psoriasis
pustular psoriasis

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What is plaque psoriasis

the most common sub-type resulting in the typical well-demarcated red, scaly patches affecting the extensor surfaces, sacrum and scalp

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What is flexural psoriasis

in contrast to plaque psoriasis the skin is smooth

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What is guttate psoriasis

transient psoriatic rash frequently triggered by a streptococcal infection. Multiple tear drop papules on the trunk and limbs

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What is pustular psoriasis

commonly occurs on the palms and soles

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Complications of psoriasis?

psoriatic arthropathy (around 10%)
increased incidence of metabolic syndrome
increased incidence of cardiovascular disease
increased incidence of venous thromboembolism
psychological distress

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Nail signs of psoriasis?

pitting
onycholysis
subungual hyperkeratosis
loss of nail

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Psoriatic nail changes affect both fingers and toes

True

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psoriatic arthropathy reflects severity of psoriasis

false

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80-90% of patients with psoriatic arthropathy have nail changes

true

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The following factors may exacerbate psoriasis:

trauma
alcohol
drugs: beta blockers, lithium, antimalarials (chloroquine and hydroxychloroquine), NSAIDs and ACE inhibitors, infliximab
withdrawal of systemic steroids

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Which infection may trigger guttate psoriasis?

It may be precipitated by a streptococcal infection 2-4 weeks prior to the lesions appearing.

Guttate psoriasis is more common in

children and adolescents

Management of guttate psoriasis?

most cases resolve spontaneously within 2-3 months
there is no firm evidence to support the use of antibiotics to eradicate streptococcal infection
topical agents as per psoriasis
UVB phototherapy
tonsillectomy may be necessary with recurrent episodes

Differentiate guttate psoriasis & pityriasis rosea prodrome?

Guttate: Classically preceded by a streptococcal sore throat 2-4 weeks

Pityriasus rosea:  majority of patients there is no prodrome, but a minority may give a history of a recent viral infection
herald patch (usually on trunk)

Describe the appearance of pityriasis rosea?

Herald patch followed 1-2 weeks later by multiple erythematous, slightly raised oval lesions with a fine scale confined to the outer aspects of the lesions.

May follow a characteristic distribution with the longitudinal diameters of the oval lesions running parallel to the line of Langer. This may produce a ‘fir-tree’ appearance

Mx pityriasis rosea?

Self-limiting, resolves after around 6 weeks

What is Pityriasis rosea?

acute, self-limiting rash which tends to affect young adults. The aetiology is not fully understood but is thought that herpes hominis virus 7 (HHV-7) may play a role.

Chronic plaque psoriasis first line?

regular emollients may help to reduce scale loss and reduce pruritus a potent corticosteroid applied once daily plus vitamin D analogue applied once daily should be applied separately, one in the morning and the other in the evening) for up to 4 weeks as initial treatment

Chronic plaque psoriasis second line? When is this indicated?

if no improvement after 8 weeks then offer: | a vitamin D analogue twice daily

Chronic plaque psoriasis third line? When is this indicated?

if no improvement after 8-12 weeks then offer either: a potent corticosteroid applied twice daily for up to 4 weeks, or a coal tar preparation applied once or twice daily short-acting dithranol can also be used

Secondary care management psoriasis?

Phototherapy | Systemic therapy

Describe phototherapy in psoriasis mx?

narrowband ultraviolet B light is now the treatment of choice. If possible this should be given 3 times a week photochemotherapy is also used - psoralen + ultraviolet A light (PUVA)

Phototherapy adverse effects?

adverse effects: skin ageing, squamous cell cancer (not melanoma)

Describe systemic therapy in psoriasis?

oral methotrexate is used first-line. It is particularly useful if there is associated joint disease ciclosporin systemic retinoids biological agents: infliximab, etanercept and adalimumab ustekinumab (IL-12 and IL-23 blocker) is showing promise in early trials

Scalp psoriasis management first line?

NICE recommend the use of potent topical corticosteroids used once daily for 4 weeks

Scalp psoriasis management second line?

if no improvement after 4 weeks then either use a different formulation of the potent corticosteroid (for example, a shampoo or mousse) and/or a topical agents to remove adherent scale (for example, agents containing salicylic acid, emollients and oils) before application of the potent corticosteroid

Face, flexural and genital psoriasis management

NICE recommend offering a mild or moderate potency corticosteroid applied once or twice daily for a maximum of 2 weeks

topical corticosteroid therapy may lead to

skin atrophy, striae and rebound symptoms systemic side-effects may be seen when potent corticosteroids are used on large areas e.g. > 10% of the body surface area

Which areas are particularly prone to steroid atrophy?

the scalp, face and flexures are particularly prone to steroid atrophy so topical steroids should not be used for more than 1-2 weeks/month

What are the limits on using corticosteroids in psoriasis?

the scalp, face and flexures are particularly prone to steroid atrophy so topical steroids should not be used for more than 1-2 weeks/month NICE recommend that we aim for a 4-week break before starting another course of topical corticosteroids they also recommend using potent corticosteroids for no longer than 8 weeks at a time and very potent corticosteroids for no longer than 4 weeks at a time

examples of vitamin D analogues include

calcipotriol (Dovonex), calcitriol and tacalcitol

How do vitamin D analogues work?

they work by ↓ cell division and differentiation → ↓ epidermal proliferation

In vitamin D analogues adverse effects are common

false adverse effects are uncommon unlike corticosteroids they may be used long-term unlike coal tar and dithranol they do not smell or stain they tend to reduce the scale and thickness of plaques but not the erythema

vitamin d analogues are safe in pregnancy

false | they should be avoided in pregnancy

How does dithranol work?

inhibits DNA synthesis | wash off after 30 mins

Adverse effects of dithranol?

adverse effects include burning, staining

Coal tar | mechanism of action not fully understood - probably inhibit DNA synthesis

true