Behind the Counter: Eczema and bacterial infections

People with eczema have a disrupted skin barrier, making them more susceptible to infections. Eczema often looks pink and red among people with lighter skin tones and purple-gray among people with darker skin tones.

Children can develop eczema anywhere on their skin, whereas adults tend to develop eczema on their face, back of the neck, elbow creases, and behind their knees.

Sometimes bacterial infections, such as impetigo, can mimic eczema, but the hallmark feature of impetigo is a honey-colored crust on the surface. People can also have both an eczema flare and a bacterial infection at the same time.

Whereas eczema involves certain areas of the skin, bacterial infections can happen anywhere. This may sound unpleasant, but bacteria, fungi, viruses, etc., are all over our skin as part of our skin’s microbiome.

Our skin protects us by creating a barrier. However, when a cut or otherwise compromises our skin barrier, it allows these invaders easy access to the skin.

Having eczema makes people more at risk for bacterial infections due to S. aureus. Healthy skin often has S. aureus on it. As long as the skin barrier is intact, there is no risk of getting a bacterial infection from this bacteria.

However, the skin barrier is disrupted for people with eczema, making it easier for S. aureus to penetrate the skin and cause bacterial infections. People with eczema also have fewer antimicrobial peptides available to fight off bacteria on the skin’s surface.

In addition, eczema-prone skin is very dry and devoid of natural oils. S. aureus is lipophobic, meaning it is “afraid of fat.”

Healthy skin usually contains protective oils full of various fats to help guard against S. aureus. Without these protective oils, S. aureus easily invades eczema-prone skin.

There is a lot a person can do to protect against bacterial infections. Washing hands with warm water and a gentle soap regularly, especially when visibly dirty, after using the toilet or before applying a medication or moisturizer, can help keep people safe.

I recommend bathing once a day with lukewarm water and using a gentle cleanser for no more than 15 minutes to help remove the surface layer of bacteria from the skin. Immediately after bathing — within 2–3 minutes — apply a strong moisturizer to help retain moisture within the skin, prevent dryness, and support the skin’s barrier. Look for products containing ceramides.

Ceramides are like mortar that hold skin cells together and help reestablish the skin barrier. People should try not to share towels or facecloths with other people. Change linens and clothing often and wash them with hot water if possible. Using white vinegar to disinfect high-touch areas such as toilet seats or door handles will also prevent bacterial infections.

Dermatologists usually prescribe the following to help reduce the inflammation associated with an eczema flare:

• topical corticosteroids
• phosphodiesterase-4 (PDE4) inhibitors (crisaborole)
• Janus kinase (JAK) inhibitors (Ruxolitinib)
• calcineurin inhibitors (pimecrolimus cream or tacrolimus ointment)

If the eczema flare is very severe, sometimes a person may need oral or injectable medications.

Classic oral medications include methotrexate, acitretin, mycophenolate mofetil, cyclosporine, and azathioprine. Abrocitinib and upadacitinib are newer oral medications that are also JAK inhibitors.

The last category of eczema treatments is medications injected into the skin, often called “injectables.” Dupilumab and Tralokinumab-ldrm are both injectables used to treat more severe eczema.

Treatment for bacterial infections is either a topical antibacterial ointment, such as mupirocin, or an oral antibiotic. A doctor may swab the skin infection to determine which particular bacteria is causing the infection before prescribing an antibiotic. This way will get the best medication for the skin infection and reduce the risk of promoting antibiotic-resistant bacteria.

Although it is best for a trained healthcare professional to help manage eczema and bacterial infections, sometimes people do not have time or access to healthcare. If someone thinks they have a bacterial infection on top of eczema spots, they can do several things to treat it.

First, people should make sure to clean the area using a gentle soap that does not irritate the skin. They can then use an over-the-counter antibacterial ointment such as Neosporin. Some people are allergic to an ingredient in Neosporin called neomycin, so if the skin worsens after using this ointment, stop using it and seek the help of a skilled healthcare professional.

Using bleach baths can also reduce the number of bacteria on the skin and the frequency of eczema flares. The American Academy of Dermatology recommends following a bleach bath regimen that includes:

• using a regular-strength, plain bleach
• measuring the amount carefully
• pouring the bleach into running water
• never applying bleach directly to eczema
• consulting with a dermatologist for timing — typically 5–10 minutes
• patting skin dry gently
• applying necessary medications afterward

Having eczema puts people more at risk for S. aureus infections due to the impaired skin barrier, fewer protective skin oils, and reduced number of antimicrobial peptides on the skin surface available to fight off bacteria.

People with eczema also have drier skin, which is a more pleasant environment for S. aureus bacteria since they are lipophobic.

However, eczema does notcause S. aureus infections.

If the skin does not have exposure to this bacteria, a person cannot get an S. aureus infection — regardless of whether they have eczema.

A honey-colored crust on the surface is the hallmark of a bacterial infection of eczema skin. The word “aurum” in Latin means gold. S. aureus is named after this word as these infections classically have this gold-colored hue.

Other signs that eczema spots could have a bacterial infection include redness around the area, pain, swelling, pus, and drainage.

If a bacterial infection becomes very severe, the bacteria can cause a systemic — throughout the body — reaction characterized by fevers, chills, low blood pressure, and muscle or joint aches.

This reaction can be life threatening and needs oral or sometimes IV antibiotic treatment. People should seek the care of a doctor right away if they notice these symptoms.

Bacterial infections associated with eczema can become systemic. Usually, S. aureus bacteria remain on the skin surface, where they are relatively harmless.

However, if they are able to penetrate the skin through a broken skin barrier, as seen in people with eczema, these bacteria can invade the bloodstream, joints, bones, lungs, brain, or heart.

Systemic bacterial infections can be life threatening. Seek the care of a skilled healthcare professional for any concerning symptoms of a systemic bacterial infection: fevers, chills, low blood pressure, and muscle or joint aches.

Dr. Joan Paul is an ABMS board certified dermatologist who specializes in psoriasis, skin cancer, skin of color, and global health. She has also completed seven medical missions in the countries of Haiti, Trinidad & Tobago, Mexico, Malawi, Uganda, India, and Botswana.