Dermatology - psoriasis Flashcards
What is psoriasis?
Chronic, genetically determined, immune-mediated, inflammatory skin condition, usually characterised by typical well-defined, scaly, plaques
When are peak incidences for psoriasis?
20s, 50s
What does psoriasis look like?
Red, scaly plagues
Often symmetrical distribution
What are some different types of psoriasis?
Chronic plague, flexural, acute guttate, scalp, palmoplanar, nail, pustular, erythrodermic
What causes psoriasis?
Overactivity of the immune system
Excessive production of TH1 cytokines inc TNF-alpha
Vascular proliferation, increased cell turnover
Genetic, environmental, infection, drugs, trauma, sunlight
What is the pathogenesis of psoriasis?
Epidermal infiltration by activated T cells = increased epidermal cell proliferation and turnover, cell cycle reduced
Excessive production of TH1 cytokines
What are some precipitants to psoriasis?
Trauma, infection, drugs (B-blockers, lithium), sunlight, stress, smoking, alcohol, HIV
What are some of the histological features of psoriasis?
Hyperkeratosis Neutrophils in stratum corneum Hypogranulosis - no granular layer Psorisiform hyperplasia T cell infiltration Dilated dermal capillaries
54yo male presents with 15yr history of scaly plaques on both elbows. Over last few months rash has spread to involve large areas of his body. Recently lost job and diagnosed with hypertension. O/E has large salmon coloured plaques on his arms, legs and back with thick scale. What is the diagnosis?
Chronic plaque psoriasis
14yo male presents with acute onset of a generalised eruption. O/E has 2-5mm multiple salmon coloured papule with a fine scale worse on the trunk and proximal extremities. Mother says he has had a throat infection 2-3wks prior to rash. What is the diagnosis?
Guttate psoriasis
32yo female with several months history of a rash on her hands and feet. She works as a beautician/masseuse. O/E the skin on the palms and soles appear thick, scaly and red with yellowish brown lesions at the edges. What is the diagnosis?
Palmo-plantar psoriasis
27yo female presents complaining of severe dandruff. Tried various shampoos with no effect. Dandruff spreading on to her face as well. O/E note thick hyperkerotic plaques in the scalp and some pitting of the nails. She also has 2 small plaques of scaly rash on the cheeks. What is the diagnosis?
Scalp psoriasis and nail psoriasis
36yo male presents with several months history of rash in armpits. He has been treated with topical and oral anti-fungal agents in past with no benefit. Skin scraping show no growth. O/E note shiny pink to red sharply demarcated plaque with no scaling. What is the diagnosis?
Flexural/inverse psoriasis
50yo female with an acute onset of generalised red, tender patches. On closer inspection of the patches multiple yellow pustules are seen. What is the diagnosis?
Pustular psoriasis
67yo male with 35yr history of chronic plaque psoriasis. Wife recently died and because his psoriasis started to flare up he was prescribed 2wks course of oral prednisolone. He presents 4wks after feeling generally unwell. O/E he has generalised erythema of the skin with fine scale. He is pyrexial and has low BP. What is the diagnosis?
Erythrodermic psoriasis
