Inflammatory Skin Diseases Flashcards
What is the definition and aetiology of eczema
Dermatitis (interchangeable) which is inflammation of the skin.
Aetiology is a combination of genetic factors such as Filaggrin mutations (filaggrin is a protein which binds keratin fibres in epidermal cells), immune and reactivity to stimuli.
What are the subtypes of eczema?
Endogenous: Atopic, seborrhoeic, discoid, varicose, pompholyx.
Exogenous: Contact or photoreaction
Describe features of atopic eczema
- Itchy inflammatory skin condition which is associated with asthma, allergic rhinitis, conjunctivitis and hay fever. It has high levels of IgE with genetic and immune aetiology. Often affects infants but 75% will grow out of it by puberty. Can affect flexures
What areas of the skin are affected in infant atopic eczema?
Often facial component with perioral sparing. Many can develop secondary infections. It can be aggravated by food
What are the complications of atopic eczema
- Bacterial infections by staphylococcus aureus.
- Viral infections eg, molluscum, viral warts or eczema herpeticum (herpes)
- It can also cause tiredness, growth reduction and have a psychological impact.
What does the following image show
Molluscum. It is a pox virus which causes umbilicated papules.
What is the management of atopic eczema?
- Emollients (min 2x daily but as much as possible),
- Topical steroids,
- Biological agent Dupilumab (IL4/13 blocker),
- Systemic drugs eg, ciclosporin or methotrexate
- Potential bandage use,
- Potential antihistamine use if urticaria,
- Antibiotics/antivirals for secondary infections
- Avoidance of exacerbating factors
Describe features of contact dermatitis
It can be irritant/allergic which is precipitated by an exogenous agent. Irritants have a direct noxious effect on the skin barrier. Allergic is a type IV hypersensitivity reaction
What are some common allergens for contact dermatitis
- Nickel: jewellery, zips, coins.
- Chromate: Cement or tanned leather,
- Cobalt: pigments/dyes,
- Colophony: Glue, adhesive tapes, plasters,
- Fragrance: cosmetics, creams or soaps
What is seborrhoeic dermatitis and its management
- Chronic scaly inflammatory condition caused by an overgrowth of pityrosporum ovale yeast.
- Thrives on oily skin and can be severe in HIV.
- Management: Medicated shampoo, eg, ketoconazole for scalp. Antimicrobial/mild steroid eg, Daktacort cream for face. Often improves with UV light
Describe features of venous dermatitis and the management
- Occurs when underlying venous disease usually due to incompetence of deep perforating veins. Stagnation of fluid causes gentle stretch of skin causing dermatitis.
- Management: emollients, mild-mod topical steroids. Compression bandages/stockings and consider venous surgical intervention.
What is Psoriasis?
T cell mediated autoimmune chronic relapsing and remitting scaling disease.
What is the pathophysiology of psoriasis?
Abnormal infiltration of T cells causes release of inflammatory cytokines and increase keratinocyte proliferation.
It has both genetic and environmental links. Risk increases with number of relatives with psoriasis.
Can cause psoriatic arthritis, metabolic syndrome, liver disease and depression.
What are the genes involved in psoriasis
PSORS genes and HLA.
What are the different types of psoriasis?
- Plaque (most common),
- Guttate,
- Pustular,
- Erythrodermic,
- Flexural (inverse of normal as it is normally on extensor surfaces),
- Palmar/plantar pustulosis (common in smokers with psoriasis)
20% of patients can develop arthritis
What does the following image show?
Guttate psoriasis. It has small teardrop-like plaques of psoriasis
What does the following image show?
Erythrodermic psoriasis. More inflammatory
