Psoriasis Flashcards
Describe psoriasis
A chronic inflammatory condition characterised by scaly erythematous plaques, which typically follows a relapsing and remitting course
What is the pathogenesis of psoriasis?
Hyperproliferation of keratinocytes in the epidermis and infiltration of inflammatory cells. Blood vessels in the dermis dilate.
What is the most common type of psoriasis?
Chronic plaque psoriasis
What types of psoriasis are there?
Chronic plaque Flexural Guttate Pustular Generalised, erythrodermic Seborrhoeic
Describe chronic plaque psoriasis
Symmetrical, well defined red plaques with a silvery scale on extensor surfaces - knees, elbows and also on scalp and sacrum
Describe flexural psoriasis
Plaques mostly in moist flexural areas - axillae, groin, submammary, umbilicus. Are less scaly and can be misdiagnosed as fungal infection (the skin can appear smooth)
Describe guttate psoriasis
Large numbers of small, tear drop shape plaques. Usually over trunk and limbs in young - esp after a strep infection (tonsillitis) and usually lasting 3-4 months (transient)
Describe pustular psoriasis
Yellow/ brown pustules within plaques affecting the palms and soles
Describe erythrodermic psoriasis
Total body redness - may cause severe systemic upset e.g dehydration, HF, infection, hypothermia, protein loss, oedema
What kind of nail changes are seen with psoriasis?
Pitting
Onycholysis - separation from nail bed
Thickening
Subungual hyperkeratosis
What is Auspitz sign?
Scratch and gentle scale removal causes capillary bleeding
What percentage of people with psoriasis develop associated psoriatic arthropathy?
5-8%
What are some triggers for psoriasis?
Stress Infections e.g streptococcal infection and guttate psoriasis Skin trauma - Koebner phenomena Drugs - beta blockers, lithium, antimalarials, iodides Alcohol Obesity Smoking Vitamin D deficiency Climate
Psychological and social effects of psoriasis are common. What should be considered?
Depression Impact on body image Impact on relationships Impact on work/ school Effects of treatment
What non cutaneous manifestations should be considered?
Joint disease Cardiovascular disease Metabolic syndrome Venous thromboembolism Mental health
What educational measures should be discussed with the patient?
Explain that it is a relapsing and remitting condition. Unlikely to be cured.
What topical treatment options are there?
Emollients Corticosteroids Vitamin D analogues Coal tar Dithranol Topical retinoids
What topical treatments should be used for plaque psoriasis?
First line: topical corticosteroids e.g Betnovate once a day e.g in the morning, plus a topical vitamin D preparation applied once a day e.g at night for up to 4 weeks
Second line: If not improvement after 8w then offer a vit D analogue BD
Third line: offer a potent corticosteroid BD or a coal tar preparation OD or BD . Short acting dithranol can also be used
Potent corticosteroids should not be used over how many weeks?
8 weeks maximum
And there should be a treatment break of 4 weeks before being restarted (during which vit D analogues can be continued)
When should phototherapy be used?
Guttate or plaque psoriasis that cannot be controlled with topical treatments or when disease is widespread.
When should oral therapies be considered?
For extensive or severe psoriasis or psoriasis with systemic involvement
What oral therapies are there?
First line: Methotrexate - avoid in young in view of long term risk of hepatic fibrosis
Ciclosporin (be aware of side effects)
Acitretin - oral retinoid
Biological agents - infliximab, etanercept
What are the side effects of topical corticosteroids?
Skin thinning Striae Telangiectasia Worsening of untreated infection Triggering an episode of pustular psoriasis
Systemic SEs if potent corticosteroids used on large areas
How do vitamin D analogues work?
Reduce cell division and differentiation, so reduce scaliness of plaques
Unlike corticosteroids, adverse effects uncommon and may be used long-term.
Avoid in pregnancy
