What is psoriasis?
A common papulo-squamous disorder affecting 2% of the population and is characterized by well-demarcated, red scaly plaques. The skin becomes inflamed and hyperproliferates at about ten times the normal rate
What immune cell is implicated in psoriasis?
T-lymphocyte
What are thought to be trigger factors for the development of psoriasis?
- Infections
- Drugs
- Trauma
- Smoking
- Alcohol
- UV light
- Genotype
What are pathological features of psoriasis?
- Increased skin turnover
- Epidermal acanthosis
- Epidermal parakeratosis
- Absent granular layer
- Polymorphonuclear abscesses in upper dermis
- Capillary dilatatio in dermis
What is the most important cytokine implicated in someone with psoriasis?
TNF-alpha - bases of some therapeutic interventions
What proportion of those with psoriasis have family members with the disease?
30%
What drugs can trigger psoriasis?
- Lithium
- NSAIDs
- B-blockers
- Antimalarials
What are typical features of psoriatic plaques?
- Symmetrical, well defined, with silvery scales
- Found on extensors surfaces
- Flexures can be affected, but plaques are less scaley
What are signs of psoriasis?
- Symmetrical, sclaey plaques on flexures
- Specific types of psoriasis - guttate, pustular, generalised
- Nail changes
- Arthritis
What is the comonest type of psoriasis?
Chronic plaque psoriasis - pinkish red sclay plaques, especially on extensor surfaces such as knees and elbows. Can be present on lower back, ears and scalp as well.
In chronic plaque psoriasis, what is the term used to describe new pllaques which have formed at sites of trauma?
Kobner phenomena
What are features of flexural psoriasis?
Well-demarcated, red glazed plaques confined to flexures such as the groin, natal cleft and sub mammary area. These are rarely scaly lesions
What are features of guttate psoriasis?
‘Raindrop-like’ psoriasis is a variant most commonly seen in children and young adults. An explosive eruption of very small circular or oval plaques appears over the trunk about 2 weeks after a streptococcal sore throat.
Where is guttate psoriasis most commonly found?
Over the trunk
What can cause guttate psoriasis?
Strep throat infection - occurs approximately 2 weeks post infection
What are features of erythrodermic psoriasis?
Usually occurs in the setting of known worsening or unstable psoriasis but may uncommonly be the first presentation of psoriasis - Acute onset of erythroderma and pustular plaques
Is erythrodermic psoriasis an emergency?
Yes
What systemic features can appear in erythrodermic psoriasis?
- Malaise
- Pyrexia
- Circulatory disturbance
What are the main types of psoriasis?
- Chronic plaque psoriasis - extensors
- Flexure psoriasis
- Guttate psoriasis
- Palmo-plantar psoriasis
- Erythrodermic psoriasis
What are features of palmo-plantar psoriasis?
Plaques: Yellow-brown pustules on palms and soles
What are nail changes seen in psoriasis?
- Pitting of the nail plate
- Distal separation of the nail plate (onycholysis)
- Yellow-brown discoloration
- Subungual hyperkeratosis
- Damaged nail matrix and lost nail plate - Rare
What proportion of those with psoriasis develop a seronegative arthritis?
5-10%
What would your differential diagnosis be for a suspected psoriatic plaque?
- Dermatitis/eczema: discoid or seborrhoeic
- Lichen planus
- Pityriasis rosea [esp. guttate psoriasis]
- 2o stage of syphilis
- Reiter’s syndrome [Esp. palmoplanar psoriasis]
- Discoid lupus
What are the general principles to managent of someone with psoriasis?
- Education
- Remove triggers
- Topical therapies
- Systemic therapies
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History, examination and classification of skin lesions23
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Psoriasis35
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Eczema/Dermatitis46
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Urticaria/Angioedema14
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Bullous disease24
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Skin tumours50
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Cutaneous signs of systemic disease60
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Erythroderma8
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Facial Rashes26
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Skin infection122
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Lichen planus10
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Acute and Emergency Dermatology58
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Common problems4
