disease profiles Flashcards
what is the aetiology of acne
Lesions arise in the pilsebasceous follicle, which becomes blocked due to abnormal keratinisation and increased production of altered sebum, leading to comedones. Blockage of pilosebaceous duct is followed alteration in its microbiome, especially involving Cutibacterium acnes. Leading to activation innate immunity. This causes an inflammatory response with influx of neutrophils that release elastase, causing connective tissue damage.
what are clinical features of acne
- non inflammatory: open comedones (blackheads) or closed comedones (white heads)
- inflammatory: papules, pustules, nodules and cysts
- scars
what is the management for acne
- Topical retinoids, azeliac acid, salicylic acid are keratolytic and help unblock pores but also cause dry flakey skin which can be combated by non-comedogenic moisteriser
- Tetracycline and erythromycin are used orally for acne
- combined oral contraceptive pill
- Oral Isotretinoin is effective for severe inflammatory acne, especially with scarring
what is rosacea
Common inflammatory rash that predominantly affects the central face. More common on fair skin. Usually starts mid adult life
what does the pathogenesis of rosacea involve
- chronic sun damage
- increased innate immune response triggered by the commercial mite Demodex folliculorum and leading to synthesis of pro-angiogenic and proinflammatory mediators
what are clinical features of rosacea
- diffuse erythema and inflammatory papules and pustule
- flushing and telangiectasia may be early feature
- papules and pustules but with no comedones
what is the management of rosacea
Supressive rather than curative
- Topical metronidazole, azelic acid or ivermectin may be used for long time control
- intermittent use of oral tetracyclines
what is the aetiology of atopic eczema
- chronic inflammatory skin disease that arises from a combination of genetic, immunological and environmental factors that lead to skin barrier dysfunction and altered skin microbiome
what is events that lead to atopic eczema
- fillagrin gene mutation: fillagrin deficiency leads to impaired skin barrier function and dry skin allowing antigens and microbes to penetrate the skin
- IgE is a key mediator of itch
- Activation of TH2 CD4 lymphocytes in the skin
- increased IL-4-5-13 levels that lead to raised IgE and IL-31
what are clinical features of atopic eczema
- elbows, knees, ankles and wrists and around the neck
- Itch.
- Dry, sensitive skin.
- Inflamed, discolored skin.
- Rough, leathery or scaly patches of skin.
- Oozing or crusting.
- Areas of swelling.
what is common with a secondary infection of eczema
- Usually by staph aureus in moist flexural areas
- pustules, oedema and golden crusted inflamed papules strongly suggest secondary infection
what is eczema herpeticum
- caused by herpes simplex virus
- Appears as multiple small blisters or punched out crusted papules that are associated with malaise and pyrexia
what investigations are done for atopic eczema
- diagnosed on history and clinical features
- raised total IgE and allergen-specific IgE and mild eosinophilia
how do you manage atopic eczema
- avoidance of irritants/allergens
- emollients
- topical therapies: steroids, immunomodulators
- adjunct therapies: oral antibiotics, sedating antihistamiens, bandaging
- phototherapy
- systemic therapy
what are clinical features of seborrhoeic eczema
- affects greasy areas
- on the face it presents with scaling and erythema around the nose, medial eyebrows, hairline and ear canals
- ## itch is variable