Psoriasis Flashcards
Psoriasis prevalence
2%
patients with psoriasis are at increased risk of
arthritis and cardiovascular disease.
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
Pathophysiology psoriasis genetics
associated HLA-B13, -B17, and -Cw6. Strong concordance (70%) in identical twins
Psoriasis is multifactorial and not fully understood
true
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
Recognised subtypes of psoriasis
plaque psoriasis
flexural psoriasis
guttate psoriasis
pustular psoriasis
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
What is flexural psoriasis
in contrast to plaque psoriasis the skin is smooth
What is guttate psoriasis
transient psoriatic rash frequently triggered by a streptococcal infection. Multiple tear drop papules on the trunk and limbs
What is pustular psoriasis
commonly occurs on the palms and soles
Complications of psoriasis?
psoriatic arthropathy (around 10%)
increased incidence of metabolic syndrome
increased incidence of cardiovascular disease
increased incidence of venous thromboembolism
psychological distress
Nail signs of psoriasis?
pitting
onycholysis
subungual hyperkeratosis
loss of nail
Psoriatic nail changes affect both fingers and toes
True
psoriatic arthropathy reflects severity of psoriasis
false
80-90% of patients with psoriatic arthropathy have nail changes
true
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
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
