Atopic dermatitis (AD) is a common condition that can be associated with many diseases. This is in part because AD can have many effects on the skin, and can also be the result of many other diseases.1
How atopic dermatitis opens the door to other diseases
AD can be the result of barrier defects, where your skin doesn’t create the barrier between your body and the outside world that it is supposed to. AD can also alter the microbiome or natural colonies of bacteria that live on your skin. Most of the time, these bacteria (along with viruses, fungi and microscopic mites) live in harmony and help each other, but atopic dermatitis can change that relationship. Finally, AD is associated with an abnormal immune response, which means that your immune system is not working the way it should, which can cause many diseases including AD.
Ichthyosis vulgaris (IV) is a disease that causes scaly, dry skin that can resemble fish scales.2 It is often associated with barrier defects. Patients with IV are at higher risk for AD as the diseases often have shared genes, specifically a loss of function in a gene known as the filaggrin (FLG) gene. This gene is, in part, responsible for the skin’s ability to keep itself moist. IV and AD are often treated the same way, but some products that help IV can irritate AD, so be aware of any side effects of treatment.1
Keratosis pilaris (KP) is a very common skin condition that creates skin plugs in the hair follicles of the skin. This creates a rash-like appearance that is sometimes called “chicken-skin.”3 It tends to just affect the appearance of the skin, but this can be embarrassing for many patients. KP also shares genes with AD including the FLG gene. There are treatments for KP but no cure. This disease is also associated with barrier defects.1
Pityriasis alba (PA) is a disease characterized by uneven patches of paler skin, which often appear more distinct in the summer when unaffected skin gets tanner.1 No one knows what causes PA and it usually heals by itself over time. There are treatments available but are often expensive, and unnecessary as the condition eventually goes away on its own. There can be scaly patches associated with PA that can be treated with emollients.1
Contact dermatitis (CD) is a condition associated with AD. There are many types of CD and they have many causes. Some CD is caused by allergies, which is often an immune reaction, though it can be a barrier defect issue as AD breaks down the skin barrier and can make the skin more sensitive to allergens. The irritant CD is also associated with AD and happens when the skin is exposed to irritants, causing an immune response. The irritant CD is thought to be associated with the FLG gene and is associated with both the immune response and barrier defects.1
Patients with AD are more likely to get infections. This is in part because of the altered microbiome of those with AD, but also because of the altered immune response.
Bacterial and viral infections
Common bacterial skin infections for those with AD include Staphylococcus aureus and Streptococcus pyogenes as well as methicillin-resistant S. aureus (MRSA) and impetigo.
Viral skin infections are less common but include eczema herpeticum, which can be serious with symptoms including fever, viral blood infections, and small, fluid-filled bumps. Eczema coxsackium is a condition that occurs when AD patients are exposed to the coxsackievirus, which causes Hand, Foot and Mouth disease. This will also cause fluid-filled bumps and can cause open sores.
Patients with AD may also be at higher risk for warts. There is also some evidence that those with AD may be at an increased risk for fungal infections due to their altered microbiome and barrier defects, but the studies, for the most part, have been inconclusive to show this relationship.1
Alopecia areata is an autoimmune disease that causes hair loss. This disease can be limited to small patches or can include scalp or total body hair loss. It is linked to AD in several studies, especially in Caucasian populations.1
Vitiligo is an autoimmune disease that is also linked to AD and is characterized by patches of skin which lose pigment, similarly to pityriasis alba. Unlike PA, vitiligo doesn’t go away. The connection between AD and vitiligo is believed to be associated with shared genes, and important because it may help clinicians find better treatment options for both conditions.1
Eczema and other skin conditions
Knowing the connections between AD and other diseases is important if at some point you need treatment for one of these associated conditions. As you may have noticed, many of these conditions have overlapping causes, and symptoms, making them fairly interconnected. If you have concerns about any of these diseases or recognize any of these symptoms, talk with your health care team about the most appropriate treatments. Make sure that you mention any medications you are currently on or any concerns about side effects.
Fenner J, Silverberg N. Skin Diseases associated with Atopic Dermatitis. Clin Dermatol. 2018. doi:10.1016/j.clindermatol.2018.05.004
Ichthyosis vulgaris - Symptoms and causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/ichthyosis-vulgaris/symptoms-causes/syc-20373754. Published 2018. Accessed August 30, 2018.
Keratosis pilaris | American Academy of Dermatology. Aad.org. https://www.aad.org/public/diseases/bumps-and-growths/keratosis-pilaris. Published 2018. Accessed August 31, 2018.