Eczema is often synonymously used with the term dermatitis, others use the term eczema to specifically refer to atopic dermatitis. Dermatitis refers to any cause of skin inflammation that affects the epidermis. Atopic dermatitis (atopic eczema) is a chronic, inflammatory condition that has a relapsing course, often starting in childhood.
🔢 Classification
Dermatitis can be subdivided into 2 types - exogenous and endogenous dermatitis.
- Exogenous dermatitis - this refers to skin inflammation caused by external factors or environmental agents.
- Allergic contact dermatitis - triggered by contact with an allergen.
- Irritant contact dermatitis - triggered by contact with a chemical or irritant.
- Photosensitive dermatitis - triggered by exposure to sunlight (may be exacerbated by medications or topical products).
- Post-traumatic dermatitis - inflammation at the site of a previous traumatic injury (burn, cut, or surgical wound).
- Drug-induced dermatitis - triggered by the use of systemic or topical medications.
- Infectious dermatitis - triggered by infections (such as impetigo, herpes simplex, tinea).
- Endogenous dermatitis - this refers to skin inflammation caused by internal factors such as genetics, immune dysregulation or associated health conditions.
- Atopic dermatitis - a chronic, relapsing form associated with a genetic predisposition. This will be the focus of the discussion on this page.
- Seborrheic dermatitis - often associated with Malassezia yeast, it is a condition that causes scaly, red patches in sebaceous glands on the upper chest and back, face and scalp.
- Discoid (nummular) dermatitis - a type of eczema characterised by round, coin-shaped patches of inflamed skin. It most commonly occurs on the arms and legs.
- Lichen simplex chronicus - thickened, scaly skin due to chronic scratching or rubbing (due to underlying conditions such as stress or other types of eczema).
- Pityriasis alba - a common skin disorder in children and young adults that presents with hypopigmented, scaly patches typically following inflammation or dryness.
- Dyshidrotic eczema (pompholyx) - a type of eczema triggered by stress, sweat or allergens and results in small, fluid-filled blisters on the palms, fingers and soles of the feet.
- Stasis dermatitis - a form of dermatitis that typically occurs in the lower legs due to chronic venous insufficiency which leads to swelling, redness and scaling.
🏘️⚠️ Epidemiology and risk factors
Atopic eczema may affect individuals of all ages but most commonly is diagnosed in children <5 years old. It is quite common, affecting 1 in 5 children in the UK and 1-3% of adults. It is more prevalent in females and those with a family history. It is also more common in urban areas and smaller families (which supports a theory of an environmental aetiology potentially).
Pathophysiology
Atopic dermatitis is caused by an interplay of issues involving genetic factors and environmental factors alike.
There is a strong genetic component as it is often seen in individuals with a history atopy. One of the most significant factors is a mutation in the filaggrin gene (FLG). Filaggrin is a protein that helps maintain the skin’s structural integrity and hydration. It does this by helping form the stratum corneum (the outermost layer of the skin) by promoting the aggregation of keratin filaments. Mutations in the FLG gene result in reduced/dysfunctional filaggrin which impairs the skin’s barrier function. This causes increased transepidermal water loss and allows for environmental allergens, irritants and microbes to initiate an inflammatory process on the skin.
Environmental factors play a role in the exacerbation and severity of the disease by triggering flares. Triggers include pollen, dust mites, foods, irritants (such as harsh soaps, detergents, synthetic fabrics), and even weather changes. The compromised skin barrier allows microbial agents (particularly Staphylococcus aureus) to colonise the skin, mediating inflammation and infection.
Chronic inflammation and scratching lead to lichenification of the skin (thickened and leathery skin).
🔢 Classification
We can divide eczema into 3 phases of life:
- Infantile phase
Typically begins after 2-3 months and continues until 2 years old. The rash is itchy and weeping. It commonly is on the face, scalp and extensor surfaces (cheeks particularly affected). Infants may experience discomfort and irritability due to itching and secondary infections that occur due to scratching and the compromised skin barrier. The nappy area is typically spared (due to moisture).
- Childhood phase
This spans from 2 years to puberty. The eczema becomes more localised and less exudative. It commonly affects flexor surfaces, wrists, ankles. If on the face it is typically just in the peri-oral and peri-orbital skin. The skin may be dry, thickened and lichenified. ~25% of patients have the presence of a Dennie-Morgan fold (an extra fold under the eye) and hyperlinear palms (increased skin creases on the palms).
- Adult phase
Eczema may persist into adulthood and beyond or it may begin de novo too. Lesions are often on the face, neck and upper chest as well as flexor surfaces. Hand eczema is seen more commmonly in adults (particularly in those with occupational exposures). The skin is typically very lichenified and dry. Dyshidrotic lesions may be present on the palms and soles.
😷 Presentation
- Erythema
- Dry skin
- Pruritus and excoriation
- Bleeding
- Dyshidrotic lesions - fluid-filled, itchy vesicles particularly on the hands and feet.
- Lichenified skin - especially in older patients who have had chronic eczema.
Lesions may appear in certain patterns:
- Flexural - found in the creases of the elbows, knees, wrists and neck.
- Discoid - coin-shaped lesions especially found on the limbs.
- Follicular - small lesions found around hair follicles.
🔍 Investigations
The diagnosis of eczema is a clinical diagnosis.
Questions to ask the patient:
- Presence of pruritus - atopic eczema is unlikely if there is no itching.
- Pattern, time of onset and history of the rash - often starts in infancy and has episodes of relapse.
- Family history or personal history of atopy - other atopic conditions such as asthma and allergic rhinitis increase the likelihood of atopic eczema.
- Triggers - patients should be asked about
- Allergens - changes in soaps and detergents (especially if the patient has previously had eczema that was well-controlled), or preservatives in perfumes, metals and latex.
- Clothing - synthetic fabrics and wool are irritating to the skin typically. Silks may impede airflow and also contain the sericin protein which some people are allergic to. Cotton is the most recommended fabric.
- Infections
- Climate - extremes of temperature may affect the eczema. Inhalant allergens such as pet dander and pollen may also trigger seasonal flares.
- Dietary factors - milk, eggs, wheat, soy and peanut make up 75% of food-induced atopic eczema cases.
- Total IgE and eosinophils may be raised on blood testing, confirming an atopic phenotype.
- Skin swabs - if there are concerns of an infection.
- Skin biopsy - if the diagnosis is uncertain of there is a need to rule out other skin conditions.
NICE requires the severity of eczema to be assessed to stratify the management of the disease:
Severity | Features |
Clear | Normal skin with no evidence of active eczema. |
Mild | Areas of dryness and infrequent itching. |
Moderate | Areas of dryness, frequent itching and redness. |
Severe | Widespread areas of dryness, itching and redness with/without excoriation, lichenification, bleeding, oozing, cracking and pigmentation changes. |
Infected | Weeping and crusting with pustules, fever or malaise. |
🧰 Management
We will discuss the management of mild, moderate, severe and infected eczema:
- Emollients - advise the patient to use it plentifully and frequently.
Managing flares
- Hydrocortisone 1% - it is a mild potency topical corticosteroid. It should be used up until 48 hours after the flare has been controlled.
- Emollients - advise the patient to use it plentifully and frequently.
Managing flares:
- Betamethasone valerate 0.025% or clobetasone butyrate 0.05% - they are moderate potency topical corticosteroids. It should be used up until 48 hours after the flare has been controlled.
- If there is a flare on delicate areas of the skin, such as the face and flexures, then use a mild potency topical corticosteroid (such as hydrocortisone 1%) and only increase to a moderate potency if necessary. It should not be used for more than 5 days.
- If there is a severe itch/urticaria → non-sedating histamine may be prescribed (fexofenadine, loratidine, acrivastine, cetirizine).
- If there is suspected eczema herpeticum → urgent hospital admission.
Preventative measures - for regions are are prone to flares.
- Maintenance topical corticosteroids
- Topical calcineurin inhibitors (tacrolimus or pimecrolimus).
👩🍼 Children <6 months old with moderate/severe eczema who are bottlefed may try a 6-8 week trial of hydrolysed protein formula milk or amino acid formula milk. If they do not respond then they should restart cow’s milk.
- Emollients - advise the patient to use it plentifully and frequently.
Managing flares:
- Betamethasone valerate 0.1% - it is a potent topical corticosteroid. It should not be used in children <12 months old.
- If there is a flare on delicate areas of the skin, such as the face and flexures, then use a moderate potency topical corticosteroid (such as betamethasone valerate 0.025% or clobetasone butyrate 0.05%) and only increase to a moderate potency if necessary. It should not be used for more than 5 days.
- If the eczema is severe and has not responded to optimum topical treatment after 1 week → urgent dermatology referral.
- If the eczema is severe and extensive and causing psychological distress → oral prednisolone (30mg OD) may be prescribed for 1 week.
- If there is a severe itch/urticaria → non-sedating histamine may be prescribed (fexofenadine, loratidine, acrivastine, cetirizine).
- If there is suspected eczema herpeticum → urgent hospital admission.
Preventative measures - for regions are are prone to flares.
- Maintenance topical corticosteroids
- Topical calcineurin inhibitors (tacrolimus or pimecrolimus).
👩🍼 Children <6 months old with moderate/severe eczema who are bottlefed may try a 6-8 week trial of hydrolysed protein formula milk or amino acid formula milk. If they do not respond then they should restart cow’s milk.
This should be done to keep the eczema at bay and prevent flares.
There are 2 options for maintenance regimens:
- Step down treatment — prescribe the lowest potency topical corticosteroid that controls the eczema — typically this will be a potency class down from what is used during a flare
- Intermittent treatment — consider one of the following two regimens:
- Weekend therapy — prescribe the usual topical corticosteroid, to be used on two consecutive days per week
- Twice weekly therapy — prescribe the usual topical corticosteroid, to be used twice a week (for example every 3–4 days)
Signs of secondary bacterial infection include weeping, pustules, crusting, fever and malaise.
If the patient is not systemically unwell then antibiotics are not routinely offered. This is due to the limited benefit they have in addition to the topical corticosteroids, risk of antimicrobial resistance. However if the patient is at risk of developing complications or the extent of the disease warrants an antibiotic prescription, then there are a few options to consider:
- Flucloxacillin
- Clarithromycin - if the patient is allergic to penicillin or if they are known to be resistant to flucloxacillin.
- Erythromycin - if the patient is allergic to penicillin and is pregnant.
- Topical fusidic acid - if there are localised areas of infection.
If the infected eczema has not responded within 2 weeks then refer urgently to dermatology.
✍️ Referral
A referral to dermatology should be made if:
- Eczema is severe and has not responded to optimum topical treatment within 1 week.
- Diagnosis is/has become uncertain.
- Management is not satisfactory.
- Patient is reacting adversely to emollients.
- Facial eczema that is treatment-resistant.
- Contact allergic dermatitis is suspected.
🚨 Complications
- Infections - bacterial infections or eczema herpeticum.
- Psychosocial issues - as eczema may affect the patient at school, work and social life. It may affect their sleep and mood as well. The psychological impact of eczema should be assessed at each consultation.
- Adverse effects to topical corticosteroids/calcineurin inhibitors