Dermatitis Flashcards
What do you give for allergic rash
Anti-histamine
Steroid
Query urticaria ??
Where is dermatitis and where does it tend to affect
Papules and vesicles on erythematous base
Flexures
Face and neck in baby
What can causes be
Endogenous
- Atopic = most common
Exogenous
What is pathology behind atopic dermatitis
Genetics - FH atopy
Enviornment
Epidermal barrier dysfunction due to fliggarin dysfunction that allows allergens and irritants to enter causing immune response and water to be lost
What genetics
Fligarrin gene
Fliggarin binds keratin and produces moisture
Atopic FH - asthma / hay fever / food allergy
What histology
Spongiosis (intracellular oedema) within epidermis
Acanthosis (thickening of epidermis)
Inflammation
What is classification of atopic
Itchy skin condition in last 2 months + 3 of
- Onset <2
- Flexural involvement
- Hx dry skin
- Hx atopy
What are clinical features
Itchy dry skin condition Affects flexures Face, eyelids + neck = common in infants Antecubital and popliteal fossa Can affect wrist, hands and ankles Tend to spare nappy area
What are acute changes
Erythema Dry scale patches Papule Vesicules Weepy (Exudative) Exudates, crusting and excoriation
What are chronic changes
Lithification - papular eruption due to scratching / thickening
Plaque
Fissures
Hypo and hyper pigmentation
What are nail changes
Ridging
Pitting
Paronychia
Onycholysis
What causes acute flares
Viral illness Stress Environment Food allergy Pet allergy Teething
What are exogenous types of exzema
Allergic Contact = child sensitised
Irritant contact = repeat contact
Lichen simplex
Photoallergic
What causes contact dermatitis
Irritant or allergic
Type 4 hypersensitivity
APC takes allergic to LN and present to T cells
What are features
Can take 48-72 hours to develop
Erythema common
Crusting and vesicles are rare
How can you Dx
Skin patch set with potential allergen
IgE
Skin swab
How do you Rx
Potent steroid
What are other endogenous causes
Discoid Venous / varicose Seborrheic Pomphoylx Asteatotic Eczema herpeticum
What is discoid
Circular plaques of eczema
Can develop at trauma / irritation sites
What cause venous eczema
Increased venous pressure due to venous stasis Lymph oedema Varicose veins Chronic swelling RT in children
What helps
Emollient
Topical steroids
Compression stockings
What does seborrheic dermatitis tend to affect
Affects areas rich in sebaceous glands
Scalp / proximal flexures / face
Usually <6 months and clears without Rx
In adults associated with Malasseizia yeast
What are features
Erythematous, sharply marginated lesions
Dermatitis + dry crusted skin
Covered with greasy looking scales
In children causes cradle cap (dry, flaky, erythematous with coarse yellow scale)
What may develop in children
Otitis externa
Blepharitis
What is associated in adults
HIV - test if severe
Parkinsonism
- can improve with L-dopa
How do you Rx
Cradle cap
- Baby oil then brushing of or white petroleum jelly over night
- Topical anti-fungal if doesn’t work
Scalp
- Anti-fungal shampoo
- Topical steroid if severe itch
Face and body
- Topical anti-fungal
- Topical steroid short term
- Recurrence common
What is pomphoylx eczema and what does it require
Very itch Sudden onset crops of vesicles Palms and soles Can lead to desquamation Requires intense steroid
What is asteatotic eczema
Very dry skin
Common with hot climate or excessive washing
Shins commonly involved
What causes eczema herpeticum
Disseminated viral infection - HSV or VZV on top of eczema
Common in children with atopic eczema where virus is able to enter skin
How does it present
Itchy clusters of blisters and erosions Widespread painful vesicular rash Fever Lethargy Irritable NOT itchy Swollen LN / lymphadenopathy
How do you Rx
Can swab to confirm
Oral or IV acyclovir if severe
Ax if bacterial superinfection on top
What is maintenance Rx for atopic dermatitis
Avoid exacerbating factor
Emollient (moisturer) to create artificial barrier
Soap substitute
Intermittent topical steroid for flare up = main stay
How d you treat flare up’s
Thicker emollient
Topical steroid
Wet wraps of emollient left over night
Treat any complications e.g. bacterial infection
IV Ax or oral steroid may be required in very severe
What are different potencies of steroid and what should you aim for
Weakest cream which controls symptoms for shortest period of time
Use once daily then alternate days
Can ue 2x daily if stubborn
Hydrocortisone = mild Eumovate = moderate Betamethasone = potent Dermovate = very potent
What are other Rx options
Calcineurin inhibitors - topical tacrolimus UVB light / phototherapy Coal tar Immunosuppression - Steroid if severe and non-responsive - Methotrexate - Azathioprine - Ciclosporin Biologic = last resort
What may you need depending on cause
Anti-histmiane if allergic for symptom relief
Anti-microbial if infection on top
Anti-viral if HSV
What if future
Biologics
What suggests will have severe eczema
3-6 months affected Severe childhood Associated atopy Small family High IgE
What is very common on top of eczema
Bacterial infection - crusted / weepy Can get viral infection - Molluscum contagiosa - Viral warts - Eczema herpeticum
How do you treat
FLucloxacillin
In contrast to contact dermatitis how would you test for food allergy
Diary IgE Skin prick = most snesitive Patch Dietary elimination
What is immediate reaction in allergy
Lip swelling Urticaria Facial redness and itchy Angioedema Anaphylaxis
What is late reaction
Worsening of eczema unresponsive to Rx GI problems FTT Severe generalised itch If this happens think food allergy
What should children with unresponsive exzemca get
Rx of hydrolysed milk especially if FTT / GI symptoms
DDX of itchy eruption
Eczema Psoriasis Scabies Urticaria Allergic reaction Autoimmune - lichen Plansu
