Psoriasis Flashcards
x
ETIOLOGY OF PSORIASIS ?
multifactorial and not yet fully understood
genetic: associated HLA-B13, -B17, and -Cw6. Strong concordance (70%) in identical twins
abnormal T cell activity stimulates keratinocyte proliferation
it is recognised that psoriasis may be worsened by ?
Skin trauma
stress
Streptococcal infection - glutamate psoriasis
trauma
alcohol
drugs: beta blockers,
lithium,
antimalarials (chloroquine and hydroxychloroquine),
NSAIDs and
ACE inhibitors,
infliximab
withdrawal of systemic steroids
flexural - sweat , friction
it is recognized that may be improved by ?
(e.g. Sunlight) by environmental factors
what are the recognised subtype of psoriasis ?
plaque psoriasis: the most common
well-demarcated red, silver scaly patches affecting the extensor surfaces, sacrum and scalp
flexural psoriasis: in contrast to plaque psoriasis the skin is smooth
occurs commonly in skin folds - armpit , groin
guttate psoriasis: transient psoriatic rash frequently triggered by a streptococcal infection. Multiple red, teardrop lesions appear on the body
pustular psoriasis = commonly occurs on the palms and soles
what is Auspitz’s sign
he appearance of small bleeding points after successive layers of scale have been removed from the surface of psoriatic papules or plaques
what are some of the major complications of psoriasis ?
psoriasis is more related to arthropathy and cardiovascular diseases
increased incidence of venous thromboembolism
psychological distress
Chronic plaque psoriasis management ?
first-line: NICE recommend:
potent corticosteroid applied once daily + 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
if no improvement after how many weeks do we start second line treatment for Chronic plaque psoriasis
8 weeks
if no improvement after 8 weeks, what do we start as second line treatment for Chronic plaque psoriasis?
a vitamin D analogue applied twice daily
when do we start third line treatment for chronic plaque psoriasis ?
if no improvement after 8-12 weeks
third line treatment for chronic plaque psoriasis ?
potent corticosteroid applied twice daily for up to 4 weeks,
a coal tar preparation applied once or twice daily
short-acting dithranol can also be used
what secondary therapy can be given in chronic plaque psoriasis ?
narrowband ultraviolet B , 3 times a week
photochemotherapy is also used - psoralen + ultraviolet A light (PUVA)
if chronic plaque psoriasis affects systematically such as joint - psoriatic arthritis ?
mild peripheral arthritis/mild axial disease may be treated with ‘just’ an NSAID
if more moderate/severe disease then methotrexate is typically used as in RA
=====
ciclosporin
systemic retinoids
biological agents: infliximab, etanercept and adalimumab
( TNF alpha is a pro-inflammatory cytokine )
ustekinumab (IL-12 and IL-23 blocker) is showing promise in early trials
apremilast: phosphodiesterase type-4 (PDE4) inhibitor → suppression of pro-inflammatory mediator synthesis and promotion of anti-inflammatory mediators
Scalp psoriasis management
potent topical corticosteroids used once daily for 4 weeks
if no improvement of scalp psoriasis after 4 weeks what is given
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
management of face / flexural or genital psoriasis management ?
mild or moderate potency corticosteroid applied once or twice daily for a MAXIMUM OF 2 WEEKS
what re some of the side effects of topical steroids ?
skin atrophy,
striae
and rebound symptoms
which type of psoriasis are most affected by topical steroid side effect ?
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
systemic side-effects may be seen when potent corticosteroids are used how ?
> 10% of the body surface area
NICE recommends 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
what are examples of fit D analogues ?
Dovonex
how does fit d analogue help psoriasis ?
↓ cell division and differentiation → ↓ epidermal proliferation
coal tar and dithranol they do not smell or stain
they tend to reduce the scale and thickness of plaques but not the ?
erythema
vit d analogues and coal should be avoided in ?
pregnancy -
Dithranol
inhibits DNA synthesis
wash off after 30 mins
Coal tar - inhibit DNA synthesis
puva in psoriasis increase risk for ?
squamous cell carcinoma
