Treatment of atopic dermatitis

What is atopic dermatitis and how is it treated?

Atopic dermatitis (atopic eczema), the most common inflammatory skin disease worldwide, involves genetic and environmental factors. It is not yet possible to modify genetic factors and it can be difficult to effectively manipulate all relevant environmental factors. There is therefore no known cure for atopic dermatitis, however treatment can control the inflammatory dermatitis and help the skin feel healthy:

• General measures
• Topical treatments
• Systemic treatments.

Atopic dermatitis, antecubital fossa

Infected weepy atopic dermatitis

Lichenified atopic dermatitis

What general measures help atopic dermatitis?

• Education: Understanding the disorder and being fully informed by health care providers is important, Effective education facilitates effective treatment.
• Skin irritants: Where possible avoid triggers that can directly inflame the skin. These may include fabrics, chemicals, humidity, and dryness.
• Food: The relationship between atopic dermatitis and food is complex. Food allergies may exacerbate atopic dermatitis, but avoidance diets do not cure the problem. Avoidance may exacerbate atopic dermatitis. Food allergy testing is needed if there is concern of an immediate life-threatening reaction (anaphylaxis).
• Psychological support: The psychological effects of atopic dermatitis are considerable, for both the sufferer and the carer. Counselling and cognitive behavioural therapy can be beneficial.

What topical treatments help atopic dermatitis?

Topical treatments can come in many forms. It is important that the correct formulation is used for the different patterns and distributions of atopic dermatitis.

• Lotion: smooth liquid. These are not greasy and cosmetically leave little or no residue. When applied to broken skin they can be very painful.
• Gel: semi-liquid and often clear.
• Foam: Bubbles within a liquid.
• Cream: Water-in-oil mix. Smooth and easy to spread especially on moist skin.
• Ointment: Oil-in-water. Greasy and more difficult to spread but better for dry skin than creams.

Over-the-counter topical treatments for atopic dermatitis

Emollients

• Emollients are an essential aspect of care for all types of dermatitis. They need to be continued long term in atopic dermatitis even if the skin looks and feels comfortable. They should be applied regularly and liberally.
• There are different formulations of emollient. Generally, the greasier the better but patient preference is important. Greasy moisturisers can be uncomfortable under clothing whereas lighter moisturisers, in lotions for example, stain less and are more comfortable. Paraffin-based emollients can soak into clothing causing a fire hazard. Emollients make the skin slippery so take care with emollients in the bath, shower, and when holding babies.
• Sodium lauryl sulphate (SLS) is a surfactant used to mix the oil and water in emollients. It irritates dermatitis when left on for prolonged periods. Emollients to be left on the skin should be SLS-free.
• Wet wraps may be used over emollients to areas of red, hot, weepy dermatitis.

[see Emollients for eczema]

Antiseptics

• It is common for patients with atopic dermatitis to have bacteria such as Staphylococcus aureus colonising the skin. Sometimes the skin can become infected by these organisms. Antiseptics can be used during an infection and to try to prevent infection, but with care as they can irritate the skin.
• Common antiseptics used to treat atopic dermatitis include:
  • Bleach bath: Add half a cap of household bleach to a full bath.
  • Potassium permanganate: Use in a weak concentration as a wet soak or in a bath. However, this antiseptic can cause permanent staining of ceramic baths and temporary brown staining of nails and skin.

Prescription topical treatments for atopic dermatitis

Coal tar

• Coal tar is a distillate from coal used in a variety of topical preparations including shampoos, lotions, and creams, sometimes mixed with a topical steroid to treat scaly atopic dermatitis. The smell can be off-putting.

Topical steroid

• Topical steroids are the mainstay treatment for mild-to-moderate atopic dermatitis. They are safe and effective when used correctly.
• The strength of a topical steroid is determined by the structure of the molecule. The weakest steroid used for the shortest time to be effective is usually prescribed. The strength of steroid selected is determined by the skin site and dermatitis severity.
• The fingertip unit is a useful guide to how much cream or ointment to apply.
• Wet wraps can be applied over a topical steroid for acutely inflamed atopic dermatitis.
• Weekend treatment: When the dermatitis is under control, apply the steroid two days per week to any new or old areas of dermatitis, and then take a break for five days.
• Fear of topical steroids resulting in their inadequate use is a common reason why they do not work.
• A rebound flare may occur if too strong a steroid is used on the incorrect site for the incorrect reason.

Topical calcineurin inhibitors

• Topical calcineurin inhibitors are topical immunomodulators and work in a different way from corticosteroids.
• Pimecrolimus and tacrolimus are suitable for treating atopic dermatitis in sensitive sites such as the eyelids, skinfolds, and genital areas.

Crisaborole ointment

• Crisaborole was approved by the FDA in 2016 as a topical treatment for mild-to-moderate atopic dermatitis in patients 2 years of age and older. It works by inhibiting phosphodiesterase 4 (PDE4). [see also Key clinical-trial evidence for crisaborole]

Phototherapy

• Narrowband UVB phototherapy can be used to treat severe atopic dermatitis.
• Treatment involves standing in the cabinet two to five times weekly, so may not be suitable for young children or the infirm who cannot stand unaided.
• Phototherapy is usually combined with the usual topical treatments.

What systemic treatments help atopic dermatitis?

Antihistamines

• Antihistamines are useful to control dermographism and other forms of urticaria in some patients with atopic dermatitis.
• There is no role for the routine use of antihistamines for dermatitis-induced itch.

Systemic steroid

• A short course of systemic corticosteroid can be very useful to quickly control a flare and to provide temporary respite especially for important occasions such as a wedding.

Immunosuppressive and anti-inflammatory agents

• Long-term control of severe disease may require an immunosuppressive or anti-inflammatory agent such as:
  • Methotrexate
  • Azathioprine
  • Ciclosporin
  • Mycophenolate mofetil
• These medications take weeks to work and careful monitoring is required.

Biological agents

• Biological agents block specific steps in the inflammatory pathway.
• Dupilumab is the first biological agent approved to treat atopic dermatitis. [see also Key clinical-trial evidence about dupilumab]

What new and emerging treatments are there for atopic dermatitis?

Topical agents

• Janus kinase inhibitors
• Phosphodiesterase 4 inhibitors

Systemic agents

• Biological agents
• Small molecule antagonists

Treatment of atopic dermatitis in skin of colour

• There is little published data on treatment of atopic dermatitis in skin of colour, in part due to under-representation in clinical trials.
• Treatments should take into account genetics, skin phototype, and cultural practices.
• Efficacy of systemic treatments may be influenced by gene polymorphisms and enzyme deficiencies affecting drug pharmacokinetics in some ethnic groups.

Treatment for infective complications of atopic dermatitis

• Oral antibiotics are important for secondary bacterial infection of atopic dermatitis. Skin swabs should be taken to determine the responsible bacteria and their antibiotic sensitivity. Bacterial resistance to multiple antibiotics is an increasing problem. Topical antibiotics should not be used as this increases bacterial resistance. Consider using a topical antiseptic instead.
• Atopic dermatitis can also be complicated by viral infections such as herpes viruses (eczema herpeticum), molluscum contagiosum, and Coxsackievirus (eczema coxsackium), which may require specific treatments.

[see Complications of atopic dermatitis]