What is atopic dermatitis?
Atopic dermatitis (AD) is the most common chronic inflammatory skin disease and appears to be increasing in prevalence.
The names atopic dermatitis and eczema can be used interchangeably and essentially mean inflammation of the skin. Atopic dermatitis is a chronic and relapsing condition that is typically inflamed, itchy and scaling.
Atopic dermatitis or eczema usually begins in infancy or early childhood in most individuals but can also occur for the first time in adulthood. 85% of all atopic dermatitis develops before five years old; however, senile-onset AD has also been more prevalent recently.
Atopic dermatitis is thought to be a genetic disease with multiple genes involved. This is further supported by the fact that it usually occurs in families and is linked together with other atopic disorders such as allergic rhinitis and asthma. These conditions may appear simultaneously or develop in succession.
Atopic dermatitis typically starts in infancy or early childhood, while asthma occurs in older children, and allergic rhinitis occurs in adolescence or adulthood. This is referred to as the “atopic march”.
It is also possible for atopic dermatitis to present for the first time later in life. Emotional stress or other stresses on the body like illness, cancers and even pregnancy can precipitate eczema for the first time at an older age.
What are the symptoms of atopic dermatitis?
The symptoms of atopic dermatitis vary from person to person. They include:
- Itchy skin that can be severe, especially at night
- Dry skin
- Red to brownish patches
- Small, raised bumps that may weep fluid and bleed when scratched.
- Thickened and hardened skin due to repeated scratching
What causes atopic dermatitis?
Atopica eczema is a genetic condition that occurs due to a combination of an impaired skin barrier (skin barrier defect), immune dysregulation (faulty immune function) and environmental factors such as stress, infection and climate.
Healthy skin retains moisture and protects you from bacteria, irritants and allergens. People that have eczema have a gene variation that prevents the skin from providing this protection.
Are there different types of atopic dermatitis?
The different types of AD can be classified according to your age and severity.
- Infantile AD: This occurs in children under the age of two and involves the cheeks, outer arms and legs, scalp, neck and trunk. It typically presents as red, oedematous (fluid-filled), oozing patches and patches which can be very widespread.
- Childhood AD: Typically affects children between the ages of two and twelve old. The classical form is flexural, involving the folds of the elbows and knees, scalp, periorificial areas, neck, wrists, hands, ankles and feet. The skin is typically very dry.
- Adult AD: As with childhood AD, this may present as flexural eczema. It may affect the palms and soles and often presents with tense, white blisters resembling tiny sago-like granules under the skin. The lesions in adulthood take on a more chronic appearance and tend to become thicker.
All types of eczema can vary in severity during any single episode.
- Acute eczema is inflamed, red, wet and weeping. It is often painful and uncomfortable.
- Subacute eczema is inflamed, often hyperpigmented, scaling and crusting.
- Chronic eczema has thickened patches of skin and sometimes nodules. This occurs when long-standing eczema is repeatedly rubbed or scratched.
How do you diagnose atopic dermatitis?
A clinical diagnosis is based on history and typical appearance, and features of the skin. There is usually no need for blood tests; however, a skin biopsy can prove the presence of atopic dermatitis if need be.
A skin biopsy could be warranted if the clinical appearance or course is atypical or if the skin does not respond to treatment as it should. In these cases, a skin biopsy is done to exclude an alternate diagnosis.
Can atopic dermatitis be cured?
Atopic dermatitis is a genetic condition that cannot be cured. However, the symptoms may go away spontaneously, with up to 70% of children with AD having the symptoms regress by puberty.
The symptoms can also come and go, with the condition being dormant for a few years at a time and recurring intermittently.
Can atopic dermatitis be prevented?
There isn’t an established primary prevention strategy for atopic dermatitis; however, the following tips can help prevent flare-ups of dermatitis and minimise the effects:
- Moisturise your skin at least twice a day.
- Identify and then avoid triggers that worsen your condition.
- Take shorter baths or showers (and use warm water, not hot water).
- Use a soap-free wash and avoid soap and bubble baths.
How is atopic dermatitis treated?
The optimal treatment is a combination of reducing the factors or triggers that have worsened eczema, repairing and maintaining the skin barrier, and controlling the immune response.
There isn’t a treatment that can permanently cure atopic dermatitis, and so treatment is aimed at treating the current skin condition and maintaining the response to treatment.
If regular moisturising and other self-care tips don’t help, your doctor may suggest some of the below treatments:
- Topical corticosteroids
Topical corticosteroids, commonly referred topical steroids, are the first-line prescribed treatments for AD and control acute flare-ups of eczema. They are anti-inflammatory and suppress the immune response that is responsible for the outbreak.
There are numerous topical steroids that vary in strength and consistency, with some mild eczema treatments available over-the-counter. Your dermatologist will prescribe the strength suitable for the area and severity of eczema at the time.
The steroid needed may vary between disease episodes, so a follow-up with your doctor is essential.
Topical steroids are best applied to the areas of eczema before applying your moisturiser. Where possible, it is also best to apply your steroid cream soon after a bath.
Topical steroids are extremely safe and effective if you use them as prescribed by your doctor and follow up regularly to monitor usage. You should stop using the steroid as soon as the flare-up is in control.
Possible side effects of long-term steroid use include stretch marks, thinning of the skin, dilated blood vessels and acne in the treated area.
- Topical calcineurin inhibitors (TCIs)
TCIs are creams that also suppress the immune response, similar to topical steroids; however, they can be used long-term as they don’t have the side effects of topical steroids.
TCIs can also be used as maintenance treatment in between flare-ups. They are often prescribed rather than topical steroids in sensitive skin areas such as the face, neck and folds. Examples of TCI’s are pimecrolimus and tacrolimus.
The most common side effects of TCIs are skin burning and irritation, which improve within 3-5 days.
There was initially some controversy that TCIs cause skin cancer; however, there is no conclusive evidence for this.
Antihistamines don’t treat AD but do provide symptomatic relief and are used for the sedative effects that can help improve sleep and reduce night-time scratching in patients with AD. A first-generation antihistamine with the effect of sedation is used, for example, hydroxyzine, diphenhydramine and chlorpheniramine.
- Systemic immunosuppressive agents
Some patients do not respond well enough to topical treatments, making it necessary to prescribe oral immunosuppressive agents such as cyclosporine, azathioprine and methotrexate.
- Other therapies
Ultraviolet phototherapy with a UV booth or UVB lamp is sometimes used for the treatment of AD.
Some studies have shown benefits from wet-wrap therapy, which involves applying wet bandages over eczema lesions after applying topical steroids and moisturiser. However, a possible side effect is a skin infection in the wrapped area.
Can atopic dermatitis cause other problems?
- Skin infections can occur more often in patients with AD due to impaired skin barrier function and bacteria that colonise the skin. It is often necessary to prescribe courses of topical and/or oral antibiotics for skin infection. Diluted bleach baths have been proven to reduce the number of S. aureus skin infections and decrease the need for oral antibiotics. Your doctor will prescribe this if necessary.
- Patients with AD are also prone to viral infections. Eczema herpeticum is a severe form of widespread herpes infection that occurs in patients with AD. It requires treatment with oral or IV antiviral medication such as acyclovir.
- Molluscum contagiosum is a viral infection causing small white bumps on the skin and is often found in children with AD. This usually resolves spontaneously.
- Food allergies may also be present in children with atopic dermatitis and forms part of the atopic condition (similar to how eczema, asthma and allergic rhinitis are associated). There is often not a clear and linear relationship where a particular food specifically worsens eczema. If there is a suspicion of a food worsening eczema, then it is best to keep a food diary to support this suspicion which can be tested. It is not recommended to avoid foods without confirming the allergy generally. This could lead to malnutrition and an unnecessary burden on a household to prepare separate meals when there is no benefit.
What’s new in atopic eczema?
New drugs called biologic agents that target the immune pathways causing AD are being investigated. Dupilumab is the first of these drugs that have received approval.
The diagnosis of AD is based on specific diagnostic criteria that consider the patient’s history and clinical manifestations. Early, consistent application of emollients (moisturisers) may help prevent AD in infants at increased risk. Your dermatologist will help determine the optimal skincare practices and topical corticosteroids for the treatment of your AD.