Atopic Dermatitis Flashcards
What are the diagnostic features of atopic dermatitis?
Pruritis
Typical eczematous morphology and age specific distribution patterns:
- face, neck and extensor extremitis in infants and young children
- flexural lesions at any age
- sparing of the groin and axillae
Supportive:
Onset during infancy or early childhood
Personal and or family history
Xerosis
What are some ass. features of atopic dermatitis
- Other filaggrin deficiency-associated conditions: keratosis pilaris, hyper-
linear palms, ichthyosis vulgaris - Follicular prominence, lichenification, prurigo lesions
- Ocular findings: recurrent conjunctivitis, anterior subcapsular cataract;
periorbital changes: pleats, darkening - Other regional findings, e.g. perioral or periauricular dermatitis, pityriasis
alba - Atypical vascular responses, e.g. midfacial pallor, white dermographism*,
delayed blanch
What are some of the triggers for atopic dermatitis?
- Climate: extremes of temperature (winter or summer), low humidity
- Irritants: wool/rough fabrics, perspiration, detergents, solvents
- Infections: cutaneous (e.g. Staphylococcus aureus, molluscum conta-
giosum, herpes simplex) or systemic (e.g. URI) - Environmental allergies: e.g. to dust mites, pollen, contact allergens
- Food allergies:
- Trigger in small minority of AD patients, e.g. 10%–30% of those with
moderate to severe, refractory AD - Common allergens: egg > milk, peanuts/tree nuts, (shell)fish, soy, wheat
- Detection of allergen-specific IgE (via blood and skin prick tests) does
not necessarily mean that allergy is triggering the patient’s AD
What are the atopic stigmata?
Xerosis
Ichyosis vulgaris
Keratosis pilaris
Palmar and plantar hyperlinearity
Dennie- Morgan lines (Symmetric, prominent horizontal fold(s) (single or double) just beneath the margin of the lower lid)
Periorbital darkening
Anterior neck folds (Horizontal folds across the middle of the anterior neck)
Hertoghe sign (Absence or thinning of the lateral eyebrows)
White dermatographism
Follicular prominance
What are the histological features of atopic dermatitis?
Spongiotic reaction pattern
Acute lesions:
- marked
spongiosis
- intraepidermal fluid collection leading to the formation
of vesicles or bullae
- some dermal oedema
- perivascular lymphocytes that extend
into the epidermis
- variable number of eosinophils
Subacute lesions:
- vesiculation is absent whereas acanthosis, hyper-
keratosis, and parakeratosis become evident
Chronic Lesions:
- epidermal thickening is more pronounced in a pattern that may be either irregular or regular (psoriasiform).
- granular layer thickening secondary to rubbing, as seen in
lichen simplex chronicus, to thinning when there is a psoriasiform
pattern, seen in some nummular lesions.
what genes is most commonly ass with Atopic Dermatitis?
Loss of function mutation in FLG (fillagrin)
What are the complications of atopic dermatitis?
Bacterial infection
- staph aureus
- strep pyogenes
Viral infection
- eczema herpeticum
- molluscum
Impaired QoL
Sleep disturbance
Psychological distress
Social isolation
What are common extra-cutaneous associations with atopic dermatitis?
Ocular disease:
- allergic rhinoconjunctivitis,
- atopic keratoconjunc-
tivitis,
- vernal keratoconjunctivitis
Psychiatric disease:
- depression
- anxiety
- sleep disorder
Cardiovascular disease
- angina
- MI
- CVA
- heart failure
Asthma
What causes atopic dermatitis?
epidermal barrier dysfunction;
immune dysregulation; and
alteration of the microbiome.
These factors are modulated by genetic and environmental factors.
What are the genes involved in Atopic dermatitis?
Long list including genes affecting epidermal proteins and those affecting immunologic proteins.
FLG and FLG2 - loss of function mutation of filaggrin is the strongest genetic factor.
What is filaggrin?
keratin filament-aggregating protein that serves as a major structural component of the stratum corneum.
List the topical treatment options for eczema
- Topical CS
- strength and vehicle depend on body site, disease severity and patient preference - Topical calcinurin inhibitor
- Tacrolimus 0.03 or 0.1%
- Pimecrolimus 1%
- best for face and body folds
- evidence for 3x week maintenance - Topical Jak inhibitor (Ruxilitinib)
- Crisaborole (PDE -4 inhibitor)
List the systemic treatment options for atopic dermatitis
- Dupilimab (anti IL4 / IL13
- mAb against alpha subunit of the IL4 receptor (shared by IL13)
2/ IL13 inhibitor = Tralokinumab
3/ Udapacitinib
- JAK inhibitor
4/ cyclosporin
5/ Methotrexate
6/ MMF
What dose of moisturiser is recommended in AD?
200 - 250g per week - children
250 - 500g per week - adults
What physical therapy is available for children with AD and how does it work?
nbUVB
UVA1
UVA combined with UVB
via
- induction of T cell apoptosis,
- reduction of dendritic cells - decreased expression of TH2 cytokins (IL - 5, 13, 31)
+ reduction of staph aureus colonisation
What is the name of the IL-13 inhibitor used in AD?
Tralokinumab
What dose of cyclosporin is commonly used for AD
3 - 5 mg / kg/ day
What dose of Azathiorine is typically used for AD?
Needs to be adjusted depending on TPMT status
True or false
Food hypersensitivity affects 50% of infants and young children with AD
False
- affects 30%
What are the 5 common allergens responsible for 90% of AD?
Egg
Milk
Peanuts
Soy
Wheat
True or false
Skin prick testing has a high positive predictive value
False
They have a high negative predictive value, but poor positive predictive value
Need clinical history or provocation test to determine RELEVANCE of a positive test
What are some adjunct treatments for AD?
Bleach baths
Antihistamins - no evidence
Melatonin
Dietary modification - no evidence in unselected patients, however good evidence if confirmed allergen
Wet wraps
List some DDX for AD
Allergic contact dermatitis
Irritant dermatitis
Nummular eczema
Photo-allergic dermatitis
Psoriasis
Seb Derm
MF
Infections
- impetigo
- scabies
Primary immunodeficiency
Drug eruption
Lupus
DM
LP
