Common Antihistamines Could Rapidly Resolve Long COVID, New Study Says

Scientists in California may have stumbled upon an unlikely cure for long COVID after two women found their symptoms significantly reduced after taking antihistamines every day.

Researchers at the University of California, Irvine, said that the middle-aged women with long COVID, or post-acute sequelae SARS-CoV-2 infection (PASC), took several options to manage their ongoing symptoms, including antihistamines.

According to the experts, most medical providers do not have any specifically recommended medicines for long COVID. However, the women said that they were able to sustain their improved condition for almost a year using antihistamines, but their discovery of the treatment happened by chance, per Fox News.

Antihistamines are common, over-the-counter medications that help patients who develop high histamine in their immune systems due to their allergies. It also helps treat other conditions like stomach aches, colds, or anxiety.

The Case Studies

One of the female patients was a Caucasian woman in her 40s who had a history of Raynaud's phenomenon, polycystic ovarian syndrome, and allergies to milk or dairy. She is a healthcare worker and was one of the first COVID-19 patients in the U.S. in 2020.

The woman developed long COVID two months after her infection. She experienced brain fog and common symptoms like fatigue and headache. One day, she took antihistamines, specifically 50mg of diphenhydramine, after her allergy was triggered by eating cheese. The patient experienced considerable relief from her fatigue the next day.

When she stopped taking antihistamines, her long COVID symptoms returned. Her doctors then prescribed her 25mg hydroxyzine for six months. The doctors increased the dosage to 50mg when her long COVID symptoms were sustained without any relapse for nine months.

The other patient was also a Caucasian woman in middle age who worked as a teacher. She has a history of asthma and allergies and regularly takes antihistamine fexofenadine to alleviate her condition. After contracting the virus from one of her kids, the teacher experienced long COVID for months.

When she ran out of fexofenadine for her allergies, she switched to 25mg diphenhydramine and then noted that she didn't experience fatigue and brain fog like she used to. The teacher continued taking diphenhydramine after she noticed her sense of smell improving as well. She is currently on 25mg diphenhydramine, which she takes at night, and 180mg fexofenadine in the morning.

The researchers published their findings in The Journal of Nurse Practitioners though they note that more studies have to be done to prove that antihistamines work for alleviating long COVID symptoms in the larger population.

Renewed Studies for Antihistamines

Meanwhile, a small study in 2021 involving 49 long COVID patients looked into how the immune system remains on a constant high alert with the symptoms. However, 70 percent of the patients who took antihistamines experienced improvements in their ongoing conditions. The findings were published in the Journal of Investigative Medicine.

The experts from the University of California, Irvine, said that these findings open the possibility of easy-to-access medications for treating long COVID. This should offer much hope for the millions of people worldwide who have been in distress for months or even years after contracting the virus.