Eczema Flashcards
Definition
Eczema = chronic, relapsing, inflammatory skin condition characterised by an itchy red rash, commonly on flexures
- Triggers: irritants, contact allergens, extremes of temperature (worse in winter), abrasive fabrics, sweating, dietary factors (10%), inhaled allergens (pollens, dust mite)
- Classified as mild, moderate, severe and infected
Eczema can be either:
- Atopic (where there is evidence of IgE antibodies to common allergens)
- Non-atopic
- Atopic eczema is classified as an allergic disease
- Many affected children have a family history of allergy, with at least 50% developing other allergic diseases and IgE antibodies to common allergens usually present
- Filaggrin gene mutations are the key genetic risk factor for eczema development due to impairment of skin barrier function
- This leads to cutaneous sensitisation to inhalant and food allergens
- This means that filaggrin gene mutations also predispose to food allergy, asthma and hay fever
- Up to 40% of young infants with severe eczema have IgE-mediated food allergy (especially egg)
- Screening via skin prick or IgE blood testing should be considered
Aetiology
Typically an episodic disease of flares and remissions
Involves genetic, immunologic and environmental factors leading to a dysfunctional skin barrier and immune system dysregulation
Pathogenesis involves a genetic deficiency of skin barrier function (filaggrin protein)
Barrier dysfunction is thought to:
- Cause water loss from skin -> dryness, itching
- Make skin susceptible to allergens -> hyperreactivity and induction of IgE autoantibodies
- Predisposes skin to colonisation or infection of microbes e.g. S. aureus
- Considered to be a Type I and Type 4 hypersensitivity reaction
20% prevalence amongst children in the UK
70-90% of cases present < 5 years, many present within the first 6 months of life
NOTE: exclusive breastfeeding may delay the onset of eczema
Symptoms and Signs
Usually long-standing history- i.e. 12 months of dry skin
Itching (pruritis)- MAIN SYMPTOM
- This leads to scratching and exacerbation of the rash
- Excoriated areas become erythematous, weeping and crusted
Distribution of the eruption changes with age
- Infants (≤ 18 months)- face, scalp, extensor surfaces of limbs (nappy area is spared) and trunk
- Younger children- extensor surfaces
- Children- flexures of limbs, creases of the face and neck
Dry skin
Lichenification (thickened skin) due to repeated scratching
Personal or family history of atopy: eczema, asthma, allergic rhinitis
Possible triggers:
- Irritant allergens, clothing
- Skin infections, concurrent illness
- Contact/ inhaled allergens
- Hormonal triggers, dietary factors
- Climate (extremes of temperatures can affect)
- Abrasive fabrics
Investigations
Diagnosis is CLINICAL
NOTE: If the disease is unusually severe, atypical or associated with unusual infections or faltering growth, an immune deficiency should be excluded
Consider food allergies -> blood or skin prick testing
Consider contact dermatitis -> patch testing
For skin dryness, check TFTs, vit D, zinc and FBC (iron levels)
Differentiate between the different severities of eczema
CLEAR- normal skin with no evidence of active eczema
Mild
Moderate
Severe
INFECTED- eczema is weeping, crusting or there are pustules with fever and malaise
IMPORTANT: remember to assess the psychological impact of eczema on the child
Consider using questionnaires such as the Children’s Dermatology Life Quality Index (CDLQI)
Management
MILD Eczema
- Prescribe generous amounts of emollients and recommend frequent and liberal use
- Consider prescribing a mild corticosteroid e.g. hydrocortisone 1% for areas of red skin
- This should be continued for 48 hours after the flare has been controlled
- Routine follow up is not normally needed
Refer for a routine dermatology appointment if the diagnosis is uncertain, current management has failed to control eczema, there is facial eczema or there is recurrent secondary infection
MODERATE Eczema
- NOTE: Emollients are used in all types of eczema
- Prescribe a moderately potent topical steroid: betamethasone valerate 0.025% or clobetasone butyrate 0.05%
- Use mildly potent topical steroid for delicate areas (e.g. face, flexures)
- MAXIMUM: 5 days’ use
- Treatment should be continued for 48 hours after the flare has been controlled
- If severe itching or urticaria- consider 1-month trial of a non-sedating antihistamine (e.g. cetirizine, loratadine, fenoxfenadine)
- If acute flare up with sleep disturbance, try sedating anti-histamine for 7-14 days
- Consider a maintenance regimen of topical corticosteroids to control areas of skin prone to frequent flares (not face, genitals or axillae)
- 2nd line: topical calcineurin inhibitors (e.g. tacrolimus/ Ella del)- only prescribed by a specialist
- Longer term with anti inflammatory properties on areas which don’t settle
Review regularly if the child is young and using a large amount of topical corticosteroids
SEVERE Eczema
- NOTE: Emollients are used in all types of eczema
- Prescribe a potent corticosteroid: betamethasone valerate 0.1% to be used on inflamed areas
- Use a moderate potency steroid for delicate areas
- Occlusive dressings or dry bandages may be useful
- Used with emollients for areas of chronic lichenified skin
- Can be used for short-term flares (7-14 days)
- These may be impregnated with zinc paste +/- tar paste
- Worn overnight or for 2-3 days at a time until skin has improved
- Short-term use of wet stockinette wraps are used
- Diluted topical steroids and emollients are mixed in
- Damp wraps are used followed by dry wraps on top
- If severe itching- consider 1 month trial of non-sedating antihistamine
- If the itching is affecting sleep, consider a sedating antihistamine e.g. chlorphenamine
If there is SEVERE, extensive eczema causing psychological distress, consider a course of oral corticosteroids
Prescribe a maintenance regimen of topical corticosteroids
INFECTED Eczema
- Swab the skin
- 1st line: PO Flucloxacillin
- Flucloxacillin is really good for skin infections
- If penicillin allergy: erythromycin or clarithromycin
- If the area of infection is localised, topical antibiotic creams or ointments
- Can be used separately or combined with corticosteroids
NOTE: topical antibiotics should NOT be used for > 2 weeks
Emollients (e.g. 50/50, Dermol, double base gel, cetraben, Adex gel, e45 cream):
- Minor differences between types (i.e. 50/50 very greasy, Dermol contains chlorhexidine, etc.)
- Cream = some water (thin, contains preservative)
- Ointment = no water (thick, no preservative)
- Apply to whole body and wait 30 minutes before applying steroid creams
- Apply with Finger-Tip Units (FTUs) / 500mg – reference: 1 FTU = palm of hand, elbows or knees
Topical corticosteroids:
- OD or BD, apply only to active areas
- Steroid ladder – Help (hydrocortisone) Every (Eumovate) Busy (Betnovate) Dermatologist (Dermovate)
SE: infections, thin skin, stretch marks, systemic side effects
Topical calcineurin inhibitors:
- Topical to active eczema areas
- Do not use under occlusive bandages
- Make sure to advice to break the scratching cycle
Indications for referral
Immediate -> eczema herpeticum
Urgent referral (<2 weeks) -> Severe atopic eczema not responded to optimum therapy within 1-week
Urgent referral (<2 weeks) -> treatment to bacterially infected eczema has failed
Non-urgent referral (>2 weeks) -> diagnosis uncertain, atopic eczema on face not responding, contact allergic dermatitis is suspected, causing significant social and psychological problems or severe recurrent infections
New drug: Dubilimab - v effective - SE: conjunctivitis
N.B. eczema herpeticum looks similar to impetigo so treat for both empirically with oral/IV ABx and oral/IV aciclovir
Complications
Causes of exacerbation of eczema:
- Bacterial infection
- Viral infection e.g. HSV
- Ingestion of an allergen e.g. egg
- Contact with an irritant or allergen
- Environment (heat, humidity)
- Change or reduction in medication
- Psychological stress
- Unexplained
Infection
Staphylococcus aureus- often presents as impetigo or worsening of eczema
- Inflammation increases the avidity of skin for S. aureus and reduces the expression of antimicrobial peptides which are needed to control microbial infections
- S. aureus thrives on atopic skin and releases superantigens which seem to worsen eczema
Herpes simplex virus- indicated by grouped vesicles and punched out erosion.
- Punched out lesions in clusters throughout the body, fever, painful!
- If near eye => get ophthalmology involved asap - as can cause irrev corneal scarring
- Disseminated HSV infection (eczema herpeticum) is a MEDICAL EMERGENCY
- HSV infection (although less frequent) can spread rapidly on atopic skin, causing an extensive vesicular reaction- eczema herpeticum
- May occur secondary to bacterial infections from Staphylococcal or streptococcal species
- Reactivation –> topical/systemic antivirals (IV aciclovir +/- opthal)
- Stop calcineurin inhib for 12-24 hrs
Superficial fungal infections
Regional lymphadenopathy is common in active eczema and resolves when the skin improves
Psychosocial problems
Prognosis
Most cases will resolve in adolescence
Tendency to gradually improve in adult life
Many children with atopic eczema will go on to develop asthma and/or hayfever
PACES
PACES Counselling:
- Explain the diagnosis (characterised by dry, itchy skin)
- Explain that it is very common, and many children grow out of it
- Explain the management (and use of steroids if necessary)
- Encourage frequent, liberal use of emollients (and as a soap substitute)
- Explain the association with other atopic conditions
- Advise avoidance of triggers (e.g. types of clothes, detergents, soaps, animals)
- Avoid scratching if possible (keep nails short, use anti-scratch mittens in infants)
- Safety net about signs of infection (oozing, red, fever) or eczema herpeticum
Information and Support:
- Itchywheezysneezy.co.uk – excellent website demonstrating how to apply emollients
- British Association of Dermatologists (BAD) – has an information leaflet on atopic eczema
- National Eczema Society – has fact sheet
Eczema herpeticum is acute and often widespread- it is treated with systemic aciclovir
Dietary elimination
- Food allergy should be suspected in young children with moderate/ severe, particularly if associated with gut dysmotility (colic, vomiting, altered bowel habit) or faltering growth
- MOST COMMON allergens resulting in eczema:
- Egg
- Cow’s milk
- Allergen specific IgE antibodies in the blood and skin-prick testing may be helpful
- Dietary elimination for 4-6 weeks may be necessary to detect a response
- This should be carried out with advise of the dietician
- A food challenge is required to be fully objective
