Atopic dermatitis (AD), the most common form of eczema in the US, is believed to be associated with an overactive immune system.
There's no one cause for AD. Rather, it's a combination of genetics, environmental factors, and dysfunction in the skin and immune systems.
Treating AD involves addressing the condition on multiple levels, including managing triggers, maintaining a healthy skin barrier, healing infections, and controlling immune system reactions and chronic inflammation.
Is that red, itchy spot on the back of your hand caused by a new soap? Was it something you ate? Are you allergic to a fabric in your clothes? Getting to the source of why you're breaking out could be simple — eliminate the food, or the cleanser, or the fabric that's causing the rash. In some cases, though, it's more complicated.
You might have heard of eczema, a condition that causes red, itchy skin that flares up periodically. An estimated 30 percent of Americans have eczema, mainly children and adolescents. While eczema is common, it's no ordinary rash, and its origins and treatments may be complicated. In fact, some forms of eczema are related to an overly robust immune response to common triggers, and at least one kind of eczema may be an autoimmune disease. (Source, Source)
In this article, we'll get to the bottom of what causes eczema, what we know about the role of genetics in its occurrence, and how eczema is diagnosed and treated.
Eczema refers to a group of inflammatory conditions characterized by dry, itchy skin, as well as rashes, scaly patches, blisters, and skin infections. There are seven types of eczema:
Each type has its own specific triggers and necessitates its own course of treatment. It is possible to have more than one kind of eczema at a time. (Source)
We don’t really know what causes eczema but scientists believe it's actually a mix of genetics and triggers. The most common form of eczema — atopic dermatitis, or atopic eczema — often occurs in people with autoimmune diseases and may itself be an autoimmune disorder. (Source, Source)
Atopic dermatitis (AD), or atopic eczema, is the most common type of eczema in the United States. It's usually diagnosed in children, making its first appearance between the ages of 3 to 6 months. It’s less common for AD to appear for the first time in adulthood, but it does happen. When adults have AD (also known as adult-onset atopic dermatitis), it usually appears on the backs of the knees, crooks of the elbows, back of the neck, and face (often around the eyes). (Source, Source, Source)
The most common form of eczema, atopic dermatitis, eludes firm classification as purely an autoimmune disorder. Rather, it's a condition influenced by various triggers and moving parts, each of which must be addressed.
We know that AD is the result of a cocktail of factors: the environment, genetics, and fallibility in the immune system. However, this doesn't necessarily qualify it as an autoimmune condition. It may be considered an allergy, since for some the symptoms of AD are provoked by specific allergens. And many with AD also have other allergies, such as food sensitivities, asthma, and hay fever. (Source)
Atopic dermatitis symptoms vary from person to person, and not everyone has all the symptoms all the time. They can sometimes disappear for years and then recur. Possible symptoms include:
According to the American Academy of Dermatology, there's no one thing that causes AD. Instead, it's the result of a combination of genetics, environmental factors, and dysfunctions that occur in the skin and in the immune system. (Source)
You're more likely to develop AD if one or both of your parents have it, or if they have other allergic disorders such as asthma or hay fever. Here's what we know about the specific genetic elements of AD.
The stratum corneum (SC), the outermost layer of the skin. contains a protein known as filaggrin, which is critical to keeping the SC healthy and hydrated. Mutations in FLG, the gene that controls production of the protein, have been shown to reduce the amount of available filaggrin. Filaggrin deficiency, or loss-of-function changes that limit its ability to do its job, can disrupt the skin barrier and increase the risk of developing atopic dermatitis. About half of patients with moderate to severe atopic dermatitis have an FLG mutation. (Source, Source)
CARD11 is another gene that has mutations associated with AD. In a study published in Nature Genetics in 2017, researchers found mutations in the CARD11 gene in eight people from four unrelated families, each of whom suffered severe AD. Some of the people with the mutation had other health issues, but not everyone did. People with severe immune disorders often have multiple medical issues, but the researchers concluded that CARD11 mutations could cause AD without comorbidities. (Source)
Both the FLG and CARD11 mutations follow an autosomal dominant pattern — that is, you only need to inherit a mutated gene from one parent to be at risk for developing AD. Should you inherit mutated genes from both parents, though, you are not only more likely to develop AD, your symptoms are likely to be more severe. (Source, Source)
A genetic predisposition means your skin is more prone to react to certain environmental factors, such as:
As mentioned above, the filaggrin protein plays an important role in the structure, formation, and maintenance of the outer layer of skin, which forms a barrier to keep moisture in and irritants out. When you don’t have enough filaggrin, your skin can become dry and itchy, and AD symptoms may be exacerbated. The damage to the barrier may also allow irritants and allergens to enter the body and interact with the immune system. (Source, Source)
If you have AD your immune system may be in overdrive, causing chronic inflammation. When your immune system is functioning as it should, white blood cells known as T cells attack foreign substances. A subset of the T cells, known as T helper-2 lymphocytes (Th2), release proteins called cytokines that influence other cells to mount an immune response. Excessive cytokine production, though, increases inflammation and can make symptoms worse. Recent research suggests Th2 cytokines interact directly with the nervous system to cause the intense itching many eczema sufferers experience. (Source, Source)
In addition, in AD the immune system produces high levels of immunoglobulin E, a protein that acts as an antibody and attacks foreign substances. Immunoglobulin E is one of five types of immunoglobulin, and it's found in high levels in people with allergies. Immunoglobulin E causes symptoms of allergies, such as itching. (Source)
Your health care provider can diagnose atopic dermatitis by looking at your skin and asking about your symptoms and medical history; no blood tests or other lab work are needed. Patch testing, in which patches are applied to your back for a period of time (usually 48 hours), might be performed, in order to rule out other skin conditions and determine whether a particular allergen is responsible for your symptoms. (Source)
Treating AD can be challenging, as it involves managing so many moving parts — triggers, inflammatory response, itch control, and making sure the skin barrier is fortified as much as it can be. (Source)
Some elements involved in the treatment of AD include:
In 2014 a team of researchers at Mt. Sinai in New York showed that dupilumab, a monoclonal antibody, helped resolve symptoms in people whose AD did not get better when they applied topical medications or avoided triggers. Dupilumab blocks specific cytokines involved in allergic inflammation and in 2017 was approved by the FDA for treatment of moderate to severe AD. By 2020, however, reports began popping up of patients developing joint and tendon pain and tenderness after being treated with dupilumab. Study of this and other monoclonal antibodies for treatment of atopic eczema continues. (Source, Source, Source)
Like most medical conditions, early diagnosis is vital to getting AD under control. And while managing the physical symptoms is key, it's also important to make sure you're getting emotional support. Adults with AD are more likely to develop depression and anxiety, due to the chronic nature of the condition and sensitivity about visible symptoms. (Source)
Atopic dermatitis has been shown to be associated with cardiovascular diseases, likely because many with AD also have cardiovascular risk factors such as sleep disturbance and alcohol and cigarette use. (Source)
There is a potential connection between AD and other autoimmune conditions that are aggravated by inflammation, including celiac disease and Crohn's Disease, as well as other atopic conditions, such as alopecia and vitiligo. (Source)
In the case of eczema caused by environmental factors, immune system dysfunction, and food allergens or food sensitivities, it is appropriate to consider lifestyle changes and advanced testing to get to the root of why eczema is popping up in the first place. Along with talking to your primary healthcare provider for eczema treatment options, turning to a Nutritional Therapy Practitioner for advanced testing to get to the root cause of your symptoms and guidance on making lifestyle changes that can reduce eczema flare-ups can allow you to better manage your situation.
NTPs at WellTheory will look for potential triggers of your eczema and support you through an elimination diet that temporarily removes foods you may have an allergy or sensitivity to and give you the option to test for environmental toxin exposures, gastrointestinal issues, and gut health to identify what may be contributing to eczema flares.
Eczema isn't one singular disease, but a group of inflammatory conditions that require different treatment and have different triggers. Atopic dermatitis, the most commonly occurring form of eczema, does involve some immune system dysfunction, but it doesn't fall neatly into the autoimmune disease category.
In living with atopic dermatitis, it's essential to be open with your healthcare provider about the state of your physical and mental health. You deserve to feel your best in every facet of your life, regardless of your diagnosis.