Dermatology Flashcards
What is psoriasis
a chronic inflammatory skin condition characterised by clearly defined, red and scaly plaques
What causes psoriasis?
Psoriasis is a multifactorial, immune-mediated genetic skin disease involving interactions between the innate and adaptive immune systems
What are the clinical features of psoriasis?
- Symmetrically distributed, red, scaly plaques with well-defined edges, often silvery white
- common sites on the scalp, elbows, and knees.
- Auspitz sign - small points of bleeding when plaques are scraped off
- Koebner phenomenon - development of psoriatic lesions on areas of skin affected by trauma
- Residual pigmentation of the skin after the lesions resolve
What nail signs are seen in psoriasis with nail involvement
- pitting
- onycholysis
- yellowing
- subungual hyperkeratosis
- loss of the nail
Describe 4 subtypes of psoriasis
- plaque psoriasis: typical well-demarcated red, scaly patches affecting the extensor surfaces, sacrum and scalp
- flexural psoriasis: affects body folds and genitalia. smooth, well-defined patches
- guttate psoriasis: typically 2-4w post-streptococcal infection. widespread small, red plaques on the body ( teardrop lesions)
- pustular psoriasis: commonly occurs on the palms and soles
What is the most common form of psoriasis
Chronic plaque psoriasis
What distinguishes small plaque psoriasis from large plaque psoriasis?
Small plaque psoriasis has plaques <3 cm, while large plaque psoriasis has plaques >3 cm.
Give 5 factors that may aggravate psoriasis
- Streptococcal infection
- stress
- alcohol
- trauma - cuts, abrasions or sunburn
- Drugs - e.g. lithium, beta-blockers, ACEi and NSAIDs
- withdrawal of steroids
How does sun exposure impact psoriasis?
typically improves psoriasis
What health conditions are commonly associated with psoriasis?
- Psoriatic arthritis
- IBD
- uveitis
- CVD (atherosclerosis)
- metabolic syndrome - obesity, HTN, T2DM, hyperlipidaemia
What general advice should patients with psoriasis follow?
- Smoking cessation
- limit alcohol consumption
- maintain optimal weight.
First line management of chronic plaque psoriasis
- a potent topical corticosteroid applied OD plus vitamin D analogue applied OD
- should be applied separately, one in the morning and the other in the evening
- for up to 4 weeks as initial treatment
- regular emollients may help to reduce scale loss and reduce pruritus
Second line management of chronic plaque psoriasis
if no improvement after 8w of first line treatment offer:
* vitamin D analogue (e.g., calcipotriol) twice daily - this can be used long-term
Third line management of chronic plaque psoriasis
If no improvement after 8-12 weeks of 2nd line treatment, offer either:
* a potent corticosteroid applied twice daily for up to 4 weeks, or
* a coal tar preparation applied once or twice daily
* consider short-acting dithranol (wash off after 30 mins)
Describe the secondary care management of chronic plaque psoriasis
Phototherapy:
* narrowband UVB light - 3x per week
* photochemotherapy is also used - psoralen + ultraviolet A light (PUVA)
Systemic therapy:
* oral methotrexate is used first-line
* ciclosporin
* systemic retinoids (e.g. acitretin)
* biologics - TNF-alpha inhibitors (e.g., adalimumab, infliximab, etanercept)
* IL-17/IL-23 inhibitors (e.g., ustekinumab).
Adverse effects of phototherapy in psoriasis treatment
- skin ageing
- squamous cell cancer
Management of scalp psoriasis
- potent topical corticosteroids used once daily for 4 weeks
if no improvement after 4 weeks then either use: - different formulation of the corticosteroid (e.g., a shampoo or mousse) and/or
- a topical agent to remove adherent scale (e.g., agents containing salicylic acid, emollients and oils) before application of the potent corticosteroid
Management of face, flexural and genital psoriasis
mild or moderate potency corticosteroid applied once or twice daily for a maximum of 2 weeks
What is acne vulgaris
the common form of acne, characterised by a mixed eruption of inflammatory and non-inflammatory skin lesions
Explain the pathophysiology of acne
- follicular epidermal hyperproliferation resulting in the formation of a keratin plug
- This in turn causes obstruction of the pilosebaceous units (contains the hair follicles and sebaceous glands)
- colonisation by the anaerobic bacterium Propionibacterium acnes
- overall inflammation
Where does acne vulgaris most commonly affect the body?
Primarily the face, but it can also involve the neck, chest, back, and more extensive areas
What are the superficial lesions of acne?
- Open and closed comedones (blackheads and whiteheads)
- Papules (small, tender red bumps) - inflammatory
- Pustules (small, white or yellow squeezable spots) - inflammatory
What are the deeper lesions of acne?
- Nodules (large painful lumps)
- pseudocysts (fluctuant swellings).
What are some secondary lesions associated with acne?
- Excoriations
- Ice pick scars are small indentations in the skin that remain after acne lesions heal
- Hypertrophic scars are small lumps in the skin that remain after acne lesions heal
- erythematous macules (flat marks)
- pigmented macules