PSORIASIS Flashcards
What is the underlying pathology in most cases of psoriasis?
Abnormally excessive and rapid growth of the epidermal layer of the skin.
What are the 6 main types of psoriasis?
Chronic plaque psoriasis (psoriasis vulgaris) Guttate psoriasis Erythrodermic psoriasis Flexural psoriasis Generalised pustular psoriasis Palmar plantar pustular psoriasis
What are the typical features of lesions associated with chronic plaque psoriasis?
Raised areas of inflamed skin covered with silvery-white scaly skin. These areas are called plaques and are most commonly found on the elbows, knees, scalp, and back.
What are the typical features of lesions associated with guttate psoriasis?
Numerous small, scaly, red or pink, droplet-like lesions (papules). These numerous spots of psoriasis appear over large areas of the body, primarily the trunk, but also the limbs and scalp.
What has been found to be a trigger for guttate psoriasis?
A streptococcal infection, typically streptococcal pharyngitis.
What are the typical features of lesions associated with erythrodermic psoriasis?
Widespread reddening and inflammation accompanied by exfoliation of the skin over most of the body surface. This is a dermatological emergency.
What are the typical features of lesions associated with flexural psoriasis?
Inflamed, bright red yet smooth (not scaly) patches of skin that may be painful and itchy, occurring in the folds of the skin (under the breasts, in the armpits, under the buttocks, near the genitals, or in the folds of the abdomen).
What is the underlying cause of flexural psoriasis?
One cause of flexural psoriasis may be yeast overgrowth, as well as high sensitivity to friction and/or sweating.
What are the typical features of lesions associated with generalised pustular psoriasis?
Widespread pustules filled with noninfectious pus surrounded by red, tender skin.
This is a dermatological emergency. Patients will experience chills, a fever, headache, rapid pulse rate, nausea, muscle weakness, or loss of appetite
What do we call generalised pustular psoriasis that occurs during pregnancy?
Impetigo herpetiformis
What are the causes of generalised pustular psoriasis?
Idiopathic
Infection
Abrupt withdrawal of topical corticosteroid treatment
Pregnancy
Hypocalcemia
Irritating topical treatment for plaque psoriasis
What are the typical features of lesions associated with palmar pustular psoriasis?
Large, yellowish pustules surrounded by red, tender, scaly skin found on the palms of the hands and the soles of the feet.
Who does palmar pustular psoriasis tend to affect?
Middle aged women who smoke.
When does psoriasis normally start?
In early adulthood. Disease starts before 40 in 75% of patients.
What is the prevalence of psoriasis?
2%
What drugs are known to cause or make psoriasis worse?
Lithium
Antimalarials
Beta blockers
Withdrawal of systemic steroids - rebound phenomenon
What types of topical therapies are used to treat psoriasis?
Emollients
1st line: Vitamin D analogues + Topical steroids
2nd line:
Keratolytics
Coal Tar
Dithranol
Retinoid therapy (vitamin A)
What type of emollient is most effective in treating psoriasis?
Ointments more than creams
What type of psoriasis are keratolytics used in?
Where the main symptom is hyperkeratotic plaques - chronic plaque psoriasis (most common form)
What types of vitamin D analogues can be used to treat psoriasis?
Calcipotriol - Dovinex
Tacalcitol
What is the main side effect to be aware of if using vitamin D analogues?
Hypercalcaemia
How is dithranol applied when treating psoriasis?
Either at night or through short contact therapy where it applied to plaques for 30 minutes and then washed off. Patients slowly increase concentration over several weeks.
What are the side effects of Dithranol?
Irritation and burning to the skin
What are the dermatological side effects of using topical steroids?
Atrophy Striae Telangiectasia Rebound psoriasis Generalised pustular psoriasis
What is the name of the topical retinoid therapy used in the treatment of psoriasis?
Tazarotene
What are the systemic therapies used in the treatment of psoriasis?
Acitretin (retinoid) Methotrexate Cyclosporin Hydroxyurea Mycophenalate mofetil
What types of psoriasis is acitretin particularly useful for?
Palmoplantar pustular psoriasis
Frequent widespread flare-ups
What are the side effects of acitretin?
Dry lips Hair loss Exfoliation Myalgia Arthralgia Elevated LFTs Elevated triglycerides Teratogenesis
What advice must you give someone before starting them on acitretin?
Blood cannot be donated for 1 year after cessation
Pregnancy must be avoided for 2 years after cessation
In what psoriasis patients are methotrexate, cyclosporin A and hydroxyurea particularly helpful?
Those with associated arthritis
Those with severe nail dystrophy
Severe refractory psoriasis
What types of non-medical therapy are used to treat psoriasis?
PUVA therapy
Narrow band UVB - used particularly in children
These are actually second line to topical treatments according to NICE
A 59 year old patient presents to dermatology outpatients clinic with a three month history of discolouration of the skin on his back. On examination there is patchy areas of mild hypo-pigmentation covering large areas of the back. You suspect a diagnosis of pityriasis versicolor. What is the likely causative organism?
Epidermophyton
Histoplasma capsulatum
Micosporum
Trichophyton
Malassezia
Malassezia
Pityriasis versicolour is caused by infection with Malassezia fungus. Initial treatment is with topical anti-fungals such as ketoconazole shampoo.
Microsporum, Trichophyton and Epidermophyton are dermatophytes and cause fungal nail infections and ringworm. Histoplasma is a fungi that can cause pneumonia in immuno-compromised patients.
A 19-year-old man is started on isotretinoin for severe nodulo-cystic acne. Which one of the following side-effects is most likely to occur?
Low mood
Thrombocytopaenia
Raised plasma triglycerides
Reversible alopecia
Dry skin
Dry skin is the most common side-effect of isotretinoin
A 14-year-old male is reviewed by his GP due to a patch of scaling and hair loss on the right side of his head. A skin scraping is sent which confirms a diagnosis of tinea capitis. Which organism is most likely to be responsible?
Trichophyton tonsurans
Microsporum distortum
Trichophyton verrucosum
Microsporum audouinii
Candida
Trichophyton tonsurans
