Inflammatory Skin Disease Flashcards
What are the causes of inflammation in eczema?
- inherited abnormalities in skin (barrier defect) leading to increased permeability and reduced antimicrobial function
- inherited abnormality in filaggrin expression resulting in disordered barrier function (filaggrin protein binds to keratin fibres in epidermal cells)
What are the different classifications of eczema/dermatitis?
- endogenous (atopic, seborrhoeic, discoid, varicose, pompholyx)
- exogenous (contact (allergic/irritant), photoreaction (allergic/drug))
Describe atopic eczema
- itchy inflammatory skin condition which tends to affect the face
- associated with asthma, allergic rhinitis, conjunctivitis, hayfever (atopy)
- high IgE immunoglobulin levels
- genetic and immune aetiology
Describe infant atopic eczema
- itchy
- occasionally vesicular
- facial component
- can cause secondary infection
- <50% after 18 months (usually remission by puberty)
- occasionally aggravated by food
What are the different complications of atopic eczema?
- bacterial infection (S. aureus)
- viral infection (molluscum (simple pox), viral warts, eczema herpeticum (HSV))
- tiredness, growth reduction, psychological impact
What is the appearance of molluscum infection?
Umbilicated papules
What is the treatment of eczema?
- emollients (replace barrier seal)
- topical steroids (mainstay of treatment)
- bandages (to stop scratching and hold emollients/topical steroids in place)
- antihistamines
- antibiotics/antivirals (for secondary infection)
- education
- avoidance of exacerbating avoidance (rarely dietary)
- systemic drugs eg. Ciclosporin, methotrexate
- biologics eg. IL4/13 blocker dupilumab
Describe contact dermatitis
- precipitated by an exogenous agent
- irritant = direct noxious effect on skin barrier
- allergic = type IV hypersensitivity reaction (cell-mediated)
What are the common allergens in contact dermatitis?
- nickel
- chromate (cement)
- cobalt (pigment, dyes)
- colophony (glue, adhesive tape, plasters)
- fragrance
Describe seborrhoeic dermatitis
- chronic scaly inflammation of the skin often though to be dandruff
- can affect the face, scalp, eyebrows (rarely upper chest)
- caused by overgrowth of P. Ovale yeast
- can be worse in teenagers (thrives in oily skin)
- severe in HIV/immune dysfunction
Describe the management of seborrhoeic dermatitis
- medicated anti-yeast shampoo (antifungal ketoconazole)
- face: anti-microbial mild steroid eg. Daktacort cream
- simple moisturiser
- rare systemic antifungal
- improves with UV/sunlight
Describe venous dermatitis
- underlying venous disease affecting the lower limbs
- caused by incompetence of deep perforating veins and increased hydrostatic pressure
Describe the management of venous dermatitis
- emollients
- mild/moderate topical steroids
- compression bandaging/stockings (aids flow and valves)
- consider early venous surgical intervention
What is psoriasis?
- chronic relapsing-remitting scaling disease which can appear at any age affecting any part of the skin
- plaques of raised areas of inflammation, skin from increased turnover, pitting of nails and onycholysis
- increased keratinocyte proliferation
- T cell mediated autoimmune disease with abnormal infiltration of exaggerated T cells which are releasing inflammatory cytokines such as IFN, interleukins and TNF
Describe the causes of psoriasis
- environmental and genetic factors
- associated with psoriatic arthritis, metabolic syndrome, liver disease/alcohol misuse, depression
- PSORS genes and HLA-Cw0602 associated with certain subtypes
List the different subtypes of psoriasis
- plaque
- guttate (tear-drop, smaller patches, can indicate risk of developing plaque type)
- erythrodermic (more inflammation)
- flexural/inverse
- palmar/plantar pustulosis
- Koebner phenomenon (at sites of trauma/scars)
What is auspitz?
Pinpoint haemorrhages caused by scratching a patch of psoriasis
What is the appearance of psoriasis?
Well defined salmon coloured plaque with scaling which can appear white if high turnover of cells, tends to be symmetrical and on extensor surfaces
Describe how the management of psoriasis is decided
Depends on:
- severity
- what the patient wants and can cope with
- if they have arthopathy (sore joints, sausage fingers)
- DLQI, PASI and PEST scoring systems
Describe the different treatments for psoriasis
- topical creams and ointments (moisturisers, steroids, salicylic acid)
- vitamin D analogues, coal tar, dithranol (slow down keratinocyte proliferation)
- phototherapy light treatment (immunosuppressant, reduces T cell proliferation, encourages vitamin D, UVB used or UVA + psoralen photosensitiser)
- systemic drugs (immunosuppressants eg. Methotrexate, acitretin (retinoid/vit A), dimethyl fumarate, apremilast, biologics eg. Adalimumab (anti-TNF))
