How Are Antihistamines Used to Treat Atopic Dermatitis?

Antihistamines are a type of medication that blocks the release of histamines, a substance released by the body’s immune system as part of an allergic reaction in response to an antigen. The primary function of histamine is to increase blood flow and nerve activity, which causes redness, rash, and itching.¹

Antihistamines are commonly used to treat allergic reactions, including hay fever, hives, and other skin reactions. Antihistamines may be used to treat the itch associated with atopic dermatitis (AD), although they have shown limited effectiveness in treating the symptoms of AD.^1,2

Topical and oral antihistamines for atopic dermatitis

Antihistamines come in topical formulations, which can be applied directly to the skin, and oral (systemic) formulations are ingested by mouth and affect the release of histamines throughout the body. In clinical trials, topical antihistamines have demonstrated little use in treating AD and are not recommended by the American Academy of Dermatology for people with AD. In addition, there are concerns with side effects with the use of topical antihistamines in people with AD.²

Oral antihistamines may be used to treat itching in people with AD, but research has not shown a significant benefit of using antihistamines in AD. Short-term, occasional use of antihistamines that are sedating may be beneficial in people who are experiencing sleep loss due to itching at night, however, the American Academy of Dermatology recommends that other treatments should be used to properly manage AD.¹

Dosing of antihistamines

Antihistamines are available over-the-counter and by prescription. The dosing should be based on the individual patient, particularly concerning their age. Many oral antihistamines have a sedating effect, which can benefit people who experience extreme itching at night and a disruption in their sleep. However, the sedating effects can negatively affect the school performance of children and impact daily functions such as driving in adults. Dosing and scheduling should take sedating effects into consideration.¹ Some antihistamines are non-sedating, and you should discuss with your physician whether these may be appropriate for you.

Side effects of antihistamines

Topical antihistamines may cause stinging or burning. They may also cause sedative effects. Widespread application, use on broken skin, and/or combined use with oral antihistamines are not recommended due to the risk of toxicity and hallucinations. Children are particularly at risk to such toxicities.²

Side effects from oral antihistamines vary by the individual medication. Common side effects of systemic antihistamines include undesired sedation, dry mouth, blurred vision, and a fast heart rate (tachycardia).¹ This is not a complete list of side effects, so consult with your doctor if you experience anything out of the norm while using antihistamines.