Dermatology Flashcards
Eczema
morphological descriptor for maculopapular erythematous rash ± scale/eroison/blistering, it is used in isolation usually to describe atopic eczema
Atopic dermatitis / atopic eczema
chronic relapsing inflammatory skin condition characterised by an itchy red rash that favours the skin creases e.g. fold of the elbow or behind knee
Epidemiology of atopic dermatitis / eczema
typically manifests in childhood (often improves in adolescence)
associated with other atopic disease e.g. asthma, allergic rhinitis, food allergies
affects ~10-30% of all children & up to 10% of all adults
Triggers for atopic dermatitis / eczema
irritants (e.g. soaps/detergents) heat very dry or very humid climate emotional stress dust mites pollen infections dietary factors (in ~50% of children) genetics
Associated conditions with atopic dermatitis / eczema
asthma
allergic rhinitis
food allergies
NB ~70% of cases have family history of atopic disease
Presentation of atopic dermatitis / eczema
intense pruritus & dry skin, redness ,swelling
distribution tends to vary with age
Infancy: face/scalp/extensor surfaces of limbs (nappy area generally spared)
Childhood: flexural creases, skin folds, extensor surfaces
adults/adolescents: flexural creases, lichenfied lesions & pruritus
Pompholyx eczema presentation
tiny vesicles on the palms and soles
intense pruritus ± burning sensation
once blisters burst skin may become dry and crack
Diagnostic criteria for eczema
Must have itchy skin condition + ≥3 of the following:
- hx of flexural itchiness
- hx of asthma / eczema
- dry skin for past year
- visible flexural eczema
- onset before 2 y/o
Investigations of atopic dermatitis / eczema
generally clinical diagnosis
consider allergy testing IgE level (↑) Radioallergosorbent test (RASTs)
Management of atopic dermatitis / eczema
Generally:
emollients & moisturisers (apply liberally & frequently, best on moist skin e.g. after shower, use 3-4/day)
soap substitutes
1st line: Topical steroids
2nd line: Topical tacrolimus / pimecrolimus
3rd line: systemic steroids
Finger tip unit
1 finger tip unit is ~0.5g
sufficient to treat area 2x size of flat adult hand
Mild topical steroids
e.g. hydrocortisone 0.5-2.5%
use in mild eczema and eczema on face
moderate strength topical steroids
e.g Eumovate, Modrasone
used in moderate eczema
potent topical steroids
e.g. Betnovate, Synalar, clobetasol
in severe eczema
NB super potent steroids include Dermovate
Eczema herpeticum
severe skin infection caused by herpes simplex virus (HSV) in a pt suffering from eczema
usually seen in children
Eczema herpeticum presentation
extensive disseminated & painful eruptions on head / upper body, erythematous skin with multiple round vesicles which may progress to pushed out lesions
the rash is painful & rapidly progressing
fever, malaise, lymphadenopathy
Eczema herpeticum investigations
may be a clincial diagnosis in those with know eczema & an acute eruption of a painful monomorphic clustered vesicle + fever & malaise
viral swabs /scrapings (for PCR of antibody fluorescence)
Eczema herpeticum management
Dermatological emergency
antiviral therapy e.g. aciclovir (PO/IV)
consider Abx for secondary bacterial infection
Discoid / Nummular eczema
chronic inflammatory skin condition charactersied by scattered well defined coin shaped & coin sized plaques of eczema
relatively common form of eczema, more frequently seen in men around the ages 50-65
Presentation of Discoid / Nummular eczema
2-5cm coin shaped / oval well demarcated erythematous plaques, pruritus, scale
primarily affects the extremities especially the legs
Investigations for Discoid / Nummular eczema
skin scrapping to exclude tinea (dermatophytosis)
Management of Discoid / Nummular eczema
rehydrate skin (shower/bathe in cool water)
emollients/moisturisers
soap substitutes
topical steroids (usually mild steroids sufficient e.g. hydrocortisone cream)
Urticaria (hives)
itchy, red, blotchy rash resulting from swelling of the superficial payer of the skin (dermis) due to mast cell degranulation & histamine release
NB angio-oedema occurs if the deeper tissues such as the lower dermis or subcutaneous tissue are involved & become swollen
Types of urticaria
Acute:
usually self limiting, causes include allergies, viral infections, skin contact with chemicals/nettles/latex, physical stimuli e.g. firm rubbing
Chronic:
maybe spontaneous, autoimmune or induced (e.g. by exercise, sun exposure etc)