Week 2 - Common Dermatological Conditions Flashcards
Papulosquamous Disorders - PsO
A chronic inflammatory disease of the skin characterised by well demarcated erythematous plaques with detachable silver scales
Frequent sites of involvement: sacrum, scalp, nails, umbilical
infrequent sites: face, flexor areas
Psoriasis (PsO)
- Genetic - arising from dysregulation of the immune system
- Greatly reduced keratinocyte turnover time
- prevalence = 3%
- Occur at any age
- Chronic, relapsing and remitting
- mild to life threatening
- associated with metabolic syndromel
PsO - different presentations
plaque
guttate
pustular psoriasis
inverse (body folds)
Complications of PsO
Psoriatic arthritis
Erthroderma
Koebner phenomenon
Impacts of PsO
Psychological
Physical
Social
Economic
Eczema
Wide category of non-infective and inflammatory skin disorders that are extremely itchy
- scaling, erythematous macules, papules, vesicales and/or plaques (often poorly defined margins)
- Conditions involce varying degrees of: inflammation, soreness, dryness, erythema, exudation, fissuring
Eczema classification
Now considered same as dermatitis
Exogenous vs exogenous eczema
Exogenous (dermatitis) - allergic, irritant, photoreactive
Endogenous eczema - asteatotic, atopic, seborrhoeic, discoid, venous (statis), pomphyolix, hand, eyelid
Unclassified - juvenile plantar dermatosis, neurodermatitis
Acute vs chronic eczema
Acute - affects epidermis and upper dermis, blistering and weeping, epidermal oedema, eryhtema, intense itching
Chronic - hyperkeratosis more common, lichenification, less weeping and vesiculation, acanthosis
Asteatotic eczema
- Common pruitic condition
- affects arms, legs, feet and hands
- elderly patients (80s)
- drying of skin and loss of lipids
more chronic in winter, resolving in summer
Nummular eczema
- coin shaped lesions that are symmetrical
- relapsing and remising condition
- affects mostly middle ages and elderly patients (unknown)
Frequently involved sites incl back of hands, extensors surfaces of legs, forearm and hips
Atopic Eczema
The itch that rashes
- occurs from 2 months to adulthood
- chronic and relapsing
- strong family history
- the ‘atopic march’
- aetiology unknown but environmental and genetic factors thought ot be involved in conjuction with FLG mutation - skin loses barrier function
Atopic eczema Essential features for Dx
- Puritis
- eczema (acute, subacute, chronic)
- Morphology and age-specific patterns:
Infants and children: face, neck and extensor involvement
Any age group - current or previous flexural lesions
-Does not involve groin or axillary areas
Contact Dermatitis - irritant vs allergic
ICD - inflammatory reaction to a noxious substance on the skin
ACD - an inflammatory reaction that is immune mediated after multiple exposures to a substance
Majority of CD cases are the result of ICD
CD accounts for 70-90% of all occupational skin diseases
ICD and ACD presentation
May present in the foot with a range of features including erthema, scaling, blistering, weeping, fissuring and intense itching
- if prolonged, skin may become lichenified and pigmented
ICD and ACD Assessment
- Good hx within timeline essential
- Rule out TP as a DDx
- Plantar area rarely affected unless macerated/damp brocken skin
- Areas affected should be in contact with allergen or irritant, other areas spared
Frequent causes of foot CD
- rubber additives and preservatives
-topical antibacterial agents - bactriban, neomycin - potassium dichromate
- nickle sulphate
- tea tree oil
Juveline plantar dermatosis
Glazed foot
no contact allergy
resistant to steriods
resolves at puberty
aetiology uncertain
- treated with cork insoles
Pompholyx
- Variant of eczema characterised by small
- intensly pruritic
- may precede eruption
- always check for tinea
- associated with hyperhidrosis and nickel allergy
Skins Natural defences
- Desquamation
- lower surface pH
- fatty layer
- langerhans cells
- bactericidal/antimicrobial peptides in sweat
- natural skin flora
Skins Infections
Bacteria
Fungi
Viral
Failures of natural defences
- due to excessive: heat, moisture, desiccation
- break in the skin occurs
Risk factors include - age
- open wounds
- immunosuppresion
- pre-existing diseases
-soiled skin/poor hygiene - drugs
Skin Infections primary due to:
Staph and step
Erysipelas
Acute infection caused by step
Typical signs = oedema, redness and tenderness
- leg/foot and face = most common
1 attack predisposes to further attacks
recurrant attacks may lead to scarring and blockage of lymphatics
