Inflammatory Skin Disease Flashcards
What is the difference between eczema and dermatitis?
Nothing, they are interchangeable
- mean inflammation of the skin
What is the aetiology of eczema?
Combination of genetic, immune and reactivity to a variety of sitmuli
How can inflammation in eczema be due to inherited abnormalities?
Due to a barrier defect
- causes increased permeability and reduced anti-microbial function
Abnormality in filaggrin expression (filament-associated protein which bind to keratin fibres in the epidermal cells)
- gene found on chromosome 1
Name the different classification/types of eczema
Endogenous
- atopic, seborrhoeic, dicoid, varicose and pmpholyx
Exogenous
- contact (allergic, irritant) and photorection (allergic, drug)
What is atopic eczema and its associations?
Itchy inflammatory skin condition with high Ig-E immunoglobulin antibody levels
Has genetic and immune aetiology
Associated with asthma, allergic rhinitis, conjunctivitis and hayfever
Where is atopic eczema found on babies?
Most prominent on the face
Flexor sites
How common is atopic eczema?
10-15% of infants are affected (remission occurs in 75% by the age of 15)
Is atopic eczema inherited?
2/3rds of people with eczema have a family history of atopy
Describe the appearance of the skin in atopic eczema.
Symmetrical background redness Broken skin Small areas of ulceration Itchy Occasionally vesicular Thickened skin Poorly defined
Why is infection of atpoic eczema more common in infants?
Babies are dirty and they drool a lot, introducing bacteria through the interrupted skin barrier
Can infant atopic eczema be caused by food?
Yes but it is more common for the existing eczema to be exacerbated by food (o.e. milk)
What are the complications of atopic eczema?
Bacterial infection - S.Aureus Viral - molluscum, viral warts, eczema herpeticum (tends to be sore) Tiredness (up all night scratching) Growth reduction Psychological impact
How is atopic eczema managed?
Emollients - endogenous oils Topical steriods - helps with itching and burning Bandages - hold topical preparations in place and stop babies scratching Antihistamines Antibiotics/anti-virals Education for parents and child Avoidance of exacerbating factor (dust) National Eczema Society
What type of hypersensitivity reaction is contact dermatitis?
Type 4 - delayed T-cell
What causes contact dermatitis?
Precipitated by an exogenous agent
- irritant (direct noxious effect on skin barrier)
- allergic - type IV hypersensitivity reaction
What are the common allergens involved in contact dermatitis?
Nickel (jewellery, zips, scissors, coins)
Chromate (cement, tanned leather)
Cobalt (Pigments/dyes)
Colophony (glue, adhesive tape, plasters)
Fragrance (cosmetics, creams and soaps)
Describe seborrhoeic dermatitis and its cause.
Chronic, scaly inflammation
Face, scalp and eyebrows - often confused with dandruff or facial psoriasis
Caused by overgrowth of Pityrosporum ovale yeast
Which group of people does seborrhoeic dermatitis affect the worst?
Teenagers, due to their sebaceous/oily skin
What kind of inflammatory skin disease is a presenting feature of severe HIV?
Seborrhoeic dermatitis
What are the management options for seborrhoeic dermatitis?
Scalp
- medicated anti-yeast shampoo (i.e. antifungal ketoconazole)
Face - anti-microbial, mild steroids (Daktacort cream) and a simple moisturiser
What causes venous dermatitis?
Underlying venous disease, affecting the lower legs
- incompetence of the deep perforating veins
- increased hydrostatic pressure
Therefore more common in the elderly population
Describe the appearance of venous dermatitis.
Dry
Itchy
Ulceration when scratched
Hyperpigmentation
How is venous dermatitis treated?
Emollient - exogenous oils
Mild/moderate topical steroid
Compression bandaging/stockings
Consider venous surgical intervention - varicose vein treatment
List the four most common types of eczema.
Atopic eczema, contact dermatitis, seborrhoeic dermatitis and varicose eczema.
What is the definition psoriasis?
A chronic relapsing and remitting scaling skin disease which may appear at any age and affect any part of the skin
Describe the pathophysiology of psoriasis.
T-cell mediated autoimmune disease
Abnormal infiltration of T-cells
- release of inflammatory cytokines including interferon, interluekins and TNF
- increases keretinocyte proliferation
What other medical conditions is psoriasis linked to?
Psoriatic arthritis
Metabolic syndrome
Liver disease/alcohol misuse
Depression
Describe the genetic component of psoriasis.
One sibling with psoriasis - 24% risk
One parent with psoriasis - 28% risk
One sibling and one parent with psoriasis - 41% risk
Two parents with psoriasis - 65% risk
Both parents and a sibling - 83% risk
PSORS genes and HLA-Cw0602 types associated in certain subtypes
Name the different types of psoriasis.
Plaque - textbook
Guttate - raindrop
Pustular
Erythrodermic - red skin
Koebner phenomenon - scratching of skin causes psoriasis
Palmar/plantar pustules - pustules on just hands and feet
Describe the skin in plaque type psoriasis.
Raised Larger than 1cm White scale on surface (hyperkeratinosis) Symmetrical Well defined Scaly Dry - no moisture
What are some of the common locations for plaque psoriasis?
Scalp (including behind and in the ears) Eyelids Mouth Lips Skin folds Hands Feet Nails
Describe some common nail changes in plaque psoriasis.
Nail pitting
Onycholysis - nail lifting off the nail bed
Skin may be affected around it
Hyperkeratosis
Describe the skin changes seen in pustular psoriasis.
White pustules
- blisters of noninfectious pus
Red skin
Different to chronic plaque psoriasis
Describe the skin changes seen in erythrodermic psoriasis.
The whole skin is red and hot Fine scale Flaky Pain and itching (systemically unwell)
How is psoriasis managed?
Scoring system - DLQI, PASI or PEST Topical creams and ointments Phototherapy light therapy Acitretin Methotrexate Ciclosporin Biological therapies - infliximab, etanercept and adalumimab
How many people with psoriasis develop psoriatic arthritis?
20%
What topical therapies are used in psoriasis treatment?
Moisturisers - help reduce dryness, flaking
Steriods - reduce autoimmune response, redness, itching and inflammation
Slow down keratinocyte proliferation
- vitamin D analogues
- coal tar
- topical retinoids (vitamin A) i.e. Tazarotene
Describe ultraviolet phototherapy in psoriasis treatment.
Non-specific immunosuppressant therapy Can reduce T-cell proliferation Encourages Vitamin D (reduces skin turnover) UV-B light most commonly used UV-A with psoralen photosensitiser
What are the risks of UV phototheapy?
Short term
- burning
Long term
- skin cancer
What are the systemic therapy treatments for psoriasis.
Immunosuppressants (methotrexate and ciclosporin)
Oral retinoids (aciretin)
Hydroxycarbamide
Fumaric acid esters (Shifts T1 immune response to Th2)
Biologics - infliximab (anti-TNF - dampens autoinflammation)
What are the side effects of bioligcal therapy?
Liver dysfunction, hypertension and risk of infection
