Although antihistamines do not help with eczema-related itchiness, they may be helpful (as a short-term approach) for sleeping when you live with atopic dermatitis, the most common type of eczema.

Eczema is a term typically used to describe atopic dermatitis, a condition of irritated, flaky, itchy skin. While atopic dermatitis is the most common form of eczema, the word “eczema” actually includes a total of seven inflammatory skin conditions with similar symptoms.

Eczema is known for its itchiness, and because itching is often associated with allergic reactions, reaching for an antihistamine might feel like the right choice.

Antihistamines for atopic dermatitis aren’t likely to cause you any harm, but they might not do much for your itch unless co-occurring allergy issues are involved.

Antihistamines may help some people living with atopic dermatitis, a type of eczema, by treating secondary conditions contributing to itch, like allergies. A doctor may also prescribe a person with atopic dermatitis to help them sleep.

Overall, however, antihistamines aren’t considered a first-line treatment for eczema because eczema isn’t a histamine-driven condition.

Histamines are chemicals your body produces as a part of its immune response. They’re released in reaction to foreign invaders like viruses and bacteria and play an important role in inflammation. Histamines are also produced in response to allergens, harmless substances your body misinterprets as threatening.

One of the side effects of histamine release is itching. Antihistamines soothe itching because they bind to histamine receptor sites on cells, blocking their effects.

Inflammation in atopic dermatitis can produce histamines, but atopic dermatitis isn’t considered a histamine-driven condition like allergies. The exact causes of atopic dermatitis are unclear, but genetic alterations, immune system dysfunction, and environmental exposures are all potential underlying factors.

A 2019 research review found no convincing evidence that antihistamines help in the treatment of eczema. However, the quality of evidence was limited, and more research is needed to understand the effect antihistamines can have on managing eczema.

What causes eczema itch?

Eczema can itch for a variety of reasons, including general dryness and skin irritation. The more you scratch, the greater irritation can become, creating a vicious cycle.

The mechanism behind eczema itch may be more complex than standard irritation, however.

According to a study in 2021, most acute itching in atopic eczema isn’t related to traditional histamine pathways, which is why antihistamines are often ineffective. Instead, it’s caused by a non-histamine chemical that also stimulates itch through a previously undiscovered neurological pathway.

Like histamines, the non-histamine chemical agitates nerve endings and creates the sensation of itching.

Antihistamines may be able to help with eczema symptoms of itching and sleep disturbance.

Although eczema itch isn’t driven primarily by histamines, histamines are still a part of your body’s inflammatory response. In some people, antihistamines may help with itch, especially if your eczema becomes worse due to co-existing allergies.

Some antihistamines can also cause drowsiness. If you’re experiencing itching and find it disrupts your ability to sleep, your doctor might recommend an antihistamine that can create sedation, like diphenhydramine (Benadryl).

When are antihistamines used for eczema?

Antihistamines are typically used when eczema is a part of the “atopic triad,” the experience of eczema, allergies, and asthma occurring comorbidly (at the same time).

Allergies are common with atopic dermatitis. As many as 63% of young children with moderate to severe eczema experience comorbid food allergies, and research also shows a positive link between eczema and seasonal allergies.

Exposure to allergens can make symptoms of eczema worse, a reason why antihistamines may provide relief for certain people.

The 2019 research review found that fexofenadine (Allegra) was the only antihistamine in research that potentially contributed to a minor improvement in eczema itching symptoms across a large sample of people.

That doesn’t mean other antihistamines won’t work for you. Eczema symptoms and management vary significantly between people. You might find your eczema responds positively to one antihistamine more than others — or not to any at all.

In addition to fexofenadine, other common antihistamines for eczema include:

  • diphenhydramine (Benadryl)
  • loratadine (Claritin)
  • chlorpheniramine (Chlor-Trimeton)
  • cetirizine (Zyrtec)
  • doxylamine (Unisom)

Many antihistamines have a broad safety profile that allows them to be available without a prescription. Side effects are usually mild if they occur and vary depending on the class of antihistamine used.

Common side effects of antihistamines include:

  • dry mouth
  • sedation
  • insomnia
  • dizziness
  • tinnitus
  • decreased coordination
  • diarrhea
  • constipation
  • fatigue
  • confusion
  • rapid heart rate
  • blurry vision
  • restlessness

Higher doses of antihistamines that exceed usage recommendations are associated with more serious adverse effects like delirium, coma, seizures, and cardiotoxicity.

Who shouldn’t take antihistamines for eczema?

In general, antihistamines aren’t recommended if you’re:

Eczema is a skin condition that can involve intense itching, but it isn’t the same as an allergic response. Itching in atopic dermatitis, the most common type of eczema, is associated with non-histamine neurological pathways. That’s why antihistamines usually aren’t effective.

If you live with co-existing allergies that worsen your eczema symptoms, antihistamines may help relieve allergy-related itching. Due to the sedating effect of some of these medications, they may also be beneficial in the short-term if eczema itching prevents you from sleeping.