Psoriasis Flashcards
What is psoriasis?
A chronic, relapsing-remitting autoimmune disorder, characterised by patchy inflammation of the skin. [NHS]
Describe the pathophysiology of psoriasis.
- Inflammation in the dermis - T cells and other WBCs migrate to the epidermis and release cytokines there.
- Premature maturation of keratinocytes
- Excessive epidermal growth
[wiki]
Describe the epidemiology of psoriasis.
Onset in 20s Unusual in <6 year olds M=F Wide variation in severity 80% is plaque psoriasis. [NHS]
What causes psoriasis?
Genetics - PSORS 1-9 susceptibility genes lead to inflammation.
Environmental triggers - change in weather, stress, chronic infections, trauma
Describe the distribution of psoriasis lesions.
Well-defined disc-shaped plaques. Most commonly extensor surfaces - knees, elbows; scalp and lower back. Can be anywhere. [nhs]
What is the most common form of psoriasis?
Psoriasis vulgaris/ plaque psoriasis. (80%) [nhs]
Describe the appearance of psoriasis lesions.
Dry, red, covered in silver scales.
Give a symptom of psoriasis.
Itchy, sore lesions
Relapsing/remitting course.
What nail changes may occur in 50% of people with psoriasis?
Dents/pits
Discolouration
abnormal growth
Onycholysis = Loosening/separation of nail from nailbed.
What may cause red glazed plaques at the underarm and groin areas in a person aged 50?
Flexural (inverse) psoriasis. Can be exacerbated by friction and sweating.
What might cause small lesions over the chest and arms in a 16-year-old, and what infections may precede it?
Guttate (eruptive) psoriasis - small ‘drop-like’ (guttate) lesions. Often follows streptococcal throat infections. (raindrops in the gutter)
Describe the management of guttate psoriasis.
Mild corticosteroids, usually clears up after treatment.
What could cause pustules on the palms and soles?
Palmoplantar pustular psoriasis. Pustules develop into brown scaly spots which then peel off.
Describe the management of mild plaque psoriasis.
Emollients
Topical vitamin D analogues, eg calcitriol - slow production of skin cells and are anti-inflammatory.
Topical corticosteroids eg betamethasone dipropionate
Topical retinoids eg tazarotene
Describe the management of moderate plaque psoriasis.
Phototherapy - natural and artificial light used to treat psoriasis. (nb: NOT a sunbed)
Describe the management of severe plaque psoriasis.
Oral methotrexate
Ciclosporin
Oral retinoids eg acitretin - induces keratinocyte differentiation, slows proliferation.
If systemic tx fails, try biologics eg Infliximab
Ciclosporin - class, mechanism?
Calcineurin inhibitor/ DMARD. Binds to cyclophilin produced by T lymphocytes, forming a complex which inhibits calcineurin, so less IL-2 is released, causing immunosuppression. [wiki]
Give 3 side-effects of ciclosporin and why they occur.
Increased infections due to immunosuppression
Feeling ‘shaky’
Hypertension - vasoconstriction in the kidneys, increases sodium reabsorption.
Loss of appetite
Muscle cramps/ pain
Increased GFR -> retention of uric acid -> Gout
Give 3 interactions of ciclosporin and what happens.
Immunisations - already immunocompromised
Clarythromycin, erythromycin - increases ciclosporin concentration
Atorvastatin - increases atorvastatin exposure -> liver damage, rhabdomyolysis.
Grapefruit juice - decreases ciclosporin exposure
Give 3 contraindications of ciclosporin
Cancer
Alcohol intake
Kidney malfunctions/ transplantation -> risk of gout
Hypertension
What can be used as an alternative to ciclosporin in people who have had a kidney transplant?
Azothiaprine. Does not carry risk of gout.
