Inflammatory Skin Disease - Psoriasis and Eczema Flashcards
1
Q
What is the pathophysiology of psoriasis?
A
- Hyperproliferative disorder where mitotic activity of basal cells and suprabasal cells is significantly increased, with cells migrating from the basal layer to the stratum corneum in just a few days
- Caused by T cell mediated autoimmune disease where there is an abnormal infiltration of T cells
- Leads to release of inflammatory cytokines (IFN, interleukins, TNG)
- Also leads to increased keratinocyte proliferatons
2
Q
What genetic factors are associated with psoriasis?
A
- PSORS genes (PSORS1 - chromosome 6)
- HLA-Cw0602
3
Q
What does plaque psoriasis look like?
A
- Thickened erythematous plaques with silver scales
- Extensor surfaces and scalp
- Well defined
- Raised >1cm
- Onycholysis and pits
- Most common form in adults
4
Q
What does guttate psoriasis look like?
A
- Second most common type
- Small raised papules across trunk and limbs
- Mildly erythematous
- Often triggered by streptococcal throat infection
- Comes in waves
- Tear drop shaped?
5
Q
What does erythrodermic psoriasis look like?
A
- Extensive erythematous inflamed areas covering most of the surface area of the skin
- Medical emergency
6
Q
What does pustular psoriasis look like?
A
- Yellow pustules present
- Not infectious
- Patients can be systemically unwell and so require admission to hospital
7
Q
How is psoriasis treated?
A
- Clinical diagnosis based on appearance
- Can use biopsy
- Topical creams and ointments (moisturisers, steroids, vitamin D analogues, coal tar, topical retinoids)
- Phototherapy light treatment (immunosuppressant)
- Acitretin
- Methotrexate (immunosuppressant)
- Cilosporin (immunosuppressant)
- Biologic therapies (infliximab, enteracept, adalumimab)
8
Q
What conditions are associated with psoriasis?
A
- Psoriatis arthritis
- Metabolic syndrome
- Liver disease/alcohol misuse
- Depression
9
Q
How does eczema (dermatitis) present in the skin?
A
- Inflammation primarily due to inherited abnormalities in skin ‘barrier defect’
- Causes increased permeability and reduces it’s antimicrobial function
- Inherited mutation in filaggrin expression (filament-associated proteins which bind kerratin fibres in epidermal cells - gene on chromosome 1)
- Dry, red, itchy and sore patches of skin over the flexor surfaces and on the face and neck
10
Q
What is atopic eczema?
A
- Itchy inflammatory skin condition where the skin has thickened and areas of ulceration are present
- Poorly defined, associated with asthma, allergic rhinitis, conjunctivitis and hayfever
- High IgE immunoglobulin antibody levels
11
Q
What is seborrhoeic eczema?
A
- Chronic, scaly inflammatory condition
- Face, scalp and eyebrows and occasionally upper chest
- Overgrowth of Pityrosporum Ovale yeast
12
Q
What is varicose eczema?
A
- Underlying venous disease and affects lower legs
- Incompetence of deep perforating veins and increased hydrostatic pressure
13
Q
What is contact (allergic) eczema?
A
- Precipitated by an exogenous substance (type IV hypersensitivity)
- Allergens include nickel, chromate, cobalt, colophony and fragrance
14
Q
How is eczema treated?
A
- Atopic (emollients, topical steroids, bandages, antihistamines, avoidance, antibiotics/antifungals)
- Seborrhoeic (anti yeast shampoo, antimicrobials, topical steroids)
- Varicose (emollients, topical steroids, compression bandages, surgery)
- Contact (avoidance)
15
Q
What are the key diffeneces between eczema and psoriasis?
A
