Atopic eczema

NOTES

Introduction
Atopic eczema (atopic dermatitis) is a common
inflammatory skin condition that typically presents
early in life.
Atopic eczema normally presents in the first few years of life and
normally follows a relapsing-remitting course. It is characterised by
a dry, cracked and itchy rash that may follow a number of patterns
of distribution. Episodic flares are followed by periods of remission,
though the interval and length of episodes vary widely and some
patients develop chronic disease without remission.

Management tends to follow a stepped approach that involves

emollients and additional agents such as topical steroids,
antihistamines and oral steroids where needed. Complications
include secondary infection and the impact of the condition on
patients quality of life and mental wellbeing.

Epidemiology
Atopic eczema is thought to affect 10-30% of
children and 2-10% of adults.
The majority of cases present early in life with an estimated 45%
of cases developing before 6 months of age, and 70-90% by the
age of 5.

The condition appears more common in those in higher

socioeconomic classes and with smaller families. It occurs in all
ethnic groups and does not show any significant gender
imbalance.
Figures from NICE CKS.

Atopy
Atopy refers to a predisposition to an abnormally
exaggerated IgE response to allergen exposure.
Atopy involves the sensitisation to allergens/antigens that are
detected by CD4+ type 2 helper (Th2) lymphocytes causing their
differentiation and resulting in an exaggerated IgE response. This
leads to increased risk of hypersensitivity reactions.

Atopic individuals are classically said to be at risk of developing a

triad of conditions; atopic eczema, allergic rhinitis and asthma.
Other conditions include food allergies and allergic conjunctivitis.
The term ‘atopic march’ refers to the progressive development of
atopic disease, often with atopic eczema presenting as an infant
followed by asthma and/or allergic rhinitis early in childhood.
Aetiology
The aetiology of atopic eczema is complex and
incompletely understood. It involves environmental,
hereditary, and immunological factors.
A family history of atopic disease increases the risk of developing
atopic eczema (as well as other atopic conditions). It is estimated
that 70% of those with atopic eczema will have a family history of
atopic disease. Twin studies have shown a concordance of 77-85%
in monozygotic twins and 15-21% in dizygotic twins.

A mutation in the FLG gene has been implicated in up to 50% of

cases. FLG encodes filaggrin, a protein required for skin to perform
its role as an effective barrier. Deficiency is thought to allow
access of antigens through the skin where they initiate an immune
and inflammatory response.

Clinical features
The onset, appearance and distribution varies
between individuals.
It often presents with scaly, itchy and erythematous patches
commonly affecting the flexures (elbow, knees, wrists). Infants
often present with rash affecting the cheeks.

Those of black ethnicity may demonstrate a different distribution

with rashes affecting the extensor surfaces. Affected skin can
develop patches of both hypo and hyperpigmentation.

Itchiness leading to scratching can be evidenced by excoriations

and with time lichenification (thickening) of the skin develops.

Differentials
There are a number of other dermatological
conditions that should be considered.
Alternative diagnosis should be considered and when necessary
excluded. These include:

• Psoriasis

• Seborrhoeic dermatitis

• Fungal infections

• Contact dermatitis

• Scabies

Diagnosis
NICE have published diagnostic criteria for eczema
in children under 12.
The diagnosis of atopic eczema is considered a clinical diagnosis
based on characteristic features (dry, itchy, erythematous or
thickened rash) in a typical distribution. Formal investigations
should not routinely be required for the diagnosis. Be aware that
atopic eczema may present with different distribution (e.g.
extensor) or patterns (e.g. follicular) in patients of Asian, black
Caribbean or black African ethnicity.

Based on the clinical features, atopic eczema can be divided into

different forms of severity.

• Mild: areas of dry skin, infrequent itching (with or without

small areas of redness)

• Moderate: areas of dry skin, frequent itching, and redness

(with or without excoriation and localized skin thickening)
 • Severe: widespread areas of dry skin, incessant itching, and
redness (with or without excoriation, extensive skin
thickening, bleeding, oozing, cracking, and alteration of
pigmentation)

NICE CG 57 (2021 update) describe a set of features diagnostic of

atopic eczema for children under the age of 12:

Atopic eczema should be diagnosed when a child has an itchy skin

condition plus 3 or more of the following:

• visible flexural dermatitis involving the skin creases, such as

the bends of the elbows or behind the knees (or visible
dermatitis on the cheeks and/or extensor areas in children
aged 18 months or under)

• personal history of flexural dermatitis (or dermatitis on the

cheeks and/or extensor areas in children aged 18 months or
under)

• personal history of dry skin in the last 12 months

• personal history of asthma or allergic rhinitis (or history of

atopic disease in a first- degree relative of children aged
under 4 years)

• onset of signs and symptoms under the age of 2 years (this

criterion should not be used in children aged under 4 years)

Healthcare professionals should be aware that in Asian, black

Caribbean and black African children, atopic eczema can affect the
extensor surfaces rather than the flexures, and discoid (circular) or
follicular (around hair follicles) patterns may be more common.
Management
The medical management of atopic eczema consists of
a stepped approach with emollients forming the
base of treatment.

Identifying triggers
Many individuals will have specific triggers that appear to cause
flares of disease. This can include perfumes, detergents, soaps,
clothes, hormones, foods and hormones.

Diaries may be of use to demonstrate temporal relationships

between triggers and flares - in particular food diaries. Food
allergies are more commonly seen in atopic individuals.

Medical management
Generally speaking a stepped approach to management is used.
Emollients sit at the base of this approach with other agents added
when indicated.

Emollients are moisturising agents that comes in the form of

ointments, creams, sprays, lotions and soap substitutes. Regular
and liberal use is advised even between flares of disease.

They help to soothe, smooth and hydrate skin in patients with both
dry or scaling disorders. Their effects are short-lived and therefore
regular application is critical.

There are many emollients and the choice depends on the

severity, location and patient preference. The formulation of an
emollient is often referred to as a 'vehicle'. For example, in topical
hydrocortisone cream, hydrocortisone is the drug and the vehicle
is the cream that helps it be applied. Emollients used alone do not
have a drug (vehicle-only). A variety of vehicles may be used:
 • Lotions (e.g. Dermol® 500 lotion, E45® lotion): high water
content. Spread easily and cooling. Not effective at
moisturising very dry skin. Quick absorption time.

• Creams (e.g. Diprobase® cream, Epaderm® cream): mixture

of fat and water. Spread easily. Not as greasy so often
preferred by patients. Need to be used frequently to help skin
repair.

• Gels (e.g. Dermol® 500 lotion, E45® lotion): high oil content.
Light and non-greasy. Need to be used frequently.

• Sprays (e.g. Emollin® spray): Useful for hard to reach areas.

Small number of preparations available.

• Ointments (e.g. Diprobase® ointment, Epaderm

ointment®): contain minimal water making them thick and
greasy. Patients may find them cosmetically displeasing. Very
effective at holding water and repairing skin. Should not use
on weeping eczema.

Emollients may also be used as soap substitutes or added to

baths/showers. Ordinary wash products can have the potential to
irritate and damage skin.

Soap substitues can be used for hand washing, showering and

bathing. Products may be prescribed that are specificaly designed
for this use or usual emollients can be used. Bath and shower oil
products may be bought over the counter. These can be added to
baths or used directly during a shower. They likely provide limited
benefit to usual emollient treatment.

Topical steroids are frequently used. These are categorised by their

potency:

• Mildly potent: examples include hydrocortisone 0.1%, 0.5%,

1.0%, and 2.5%
 • Moderately potent: examples include clobetasone butyrate
0.05% (Eumovate®)

• Potent: examples include betamethasone valerate 0.1%

(Betnovate®)

• Very potent: examples include clobetasol propionate 0.05%

(Dermovate®)

The use of more potent options is typically controlled by

specialists. Patients requiring this level of treatment will normally
meet the requirements of specialist referral. Local side effects are
common and may include a burning sensation, thinning of skin,
contact dermatitis, acne and depigmentation. Doses vary
depending on location of the rash and patients/family should be
given clear instructions.

Topical calcineurin inhibitors (tacrolimus and pimecrolimus) may

be used in moderate to severe disease with appropriate specialist
input, typically when topical corticosteroids have failed. As the
name suggests they inhibit calcineurin inhibitors, a chemical that
normally activates T-lymphocytes.

• Topical tacrolimus: may be used in those aged 2 and over

with moderate-severe disease and where topical
corticosteroids have not controlled symptoms and there is a
risk of important adverse effects from further topical
corticosteroids (e.g. skin atrophy).

• Topical pimecrolimus: may be used in those aged 2-16 with

moderate disease on the face and neck and where topical
corticosteroids have not controlled symptoms and there is a
risk of important adverse effects from further topical
corticosteroids (e.g. skin atrophy).

NICE CG 57 (2021 update) describes the following stepped

apprach to management:
 • Mild:

• Emollients
• Mild potency topical corticosteroids
• Moderate:

• Emollients
• Moderate potency topical corticosteroids
• Topical calcineurin inhibitors
• Bandages
• Severe:

• Emollients
• Potent topical corticosteroids
• Topical calcineurin inhibitors
• Bandages
• Phototherapy
• Systemic therapy
Specialist referral should be made where disease is not well
controlled, severe, affecting the face or where the diagnosis is
uncertain. Patients affected by complications - infections or
disease impacting quality of life - should also be referred.

Psychosocial wellbeing
The impact of atopic eczema on an individuals emotional wellbeing
varies. At each assessment the impact of their disease on their
mental health and quality of life should be assessed.

Where necessary further support, treatment, referral and review

should be offered.
Complications
Complications of eczema include secondary
infection and a negative impact on an individuals
quality of life.