Over-the-counter antihistamines, usually taken for allergic reactions, could assist relieve the debilitating signs of lengthy COVID in some folks, a brand new case report suggests.
The report, revealed Feb. 7 in The Journal for Nurse Practitioners, included two middle-age girls with lengthy COVID, a situation additionally identified by the medical time period “post-acute sequelae of COVID-19” (PASC). After catching COVID-19 in 2020, the ladies developed a slew of signs that lingered for a lot of months after their preliminary infections had cleared; these long-lasting signs included cognitive impairment, pores and skin rashes and bruising, chest ache and profound fatigue.
In some unspecified time in the future, many months after first growing these signs, each people took antihistamines for unrelated allergic reactions. They discovered that, unexpectedly, their lengthy COVID signs improved after they took the medicine. Each people now take a every day routine of antihistamines and have mentioned they’ve almost regained their pre-PASC degree of functioning, in accordance with the case report.
These two anecdotal studies align with the outcomes of a bigger research, revealed Oct. 5, 2021 in The Journal of Investigative Drugs, which included 49 lengthy COVID sufferers. Of those sufferers, 26 got antihistamines. Of those, 19 reported full or partial decision of their signs. By comparability, solely six of the opposite 23 sufferers, who weren’t given antihistamines, reported improved signs in the identical time interval.
These two studies add to a rising physique of proof that antihistamines could also be useful for treating lengthy COVID, mentioned Dr. Lawrence Afrin, senior guide in hematology/oncology on the AIM Middle for Personalised Drugs in Buy, New York, who was not concerned in both research. “The one query then turns into, ‘What is the mechanism by which these medicine assist?'” he mentioned. Afrin and his colleagues suspect that mast cells, which launch histamine, could go haywire in some sufferers following a COVID-19 an infection and unleash a flood of the substance into the physique.
Antihistamines may theoretically sluggish the flood to a trickle, as there’s proof that the medicine may also help tune down the exercise of mast cells, Afrin mentioned; and naturally, the medicine additionally block histamine from plugging into cells all through the physique. That mentioned, extra analysis is required to verify the precise position of mast cells in lengthy COVID, Afrin mentioned.
The brand new case report
Research co-author Natalie Lambert, an affiliate analysis professor of biostatistics and well being information sciences on the Indiana College Faculty of Drugs, initially recognized the 2 sufferers featured within the case report. Each sufferers had been members of Survivor Corps, a digital COVID-19 analysis and advocacy group hosted on Fb; they’d each posted about how antihistamines appeared to alleviate their lengthy COVID signs.
Antihistamines block the compound histamine from plugging into receptors on cells within the physique; the medicine usually block both the H1 or H2 receptor. On the whole, immune cells launch histamine after they sense a pathogen, like a virus or bacterium, or a international substance like pollen, and the compound triggers irritation and swelling. Along with inflicting allergic reactions, histamine also can act as a chemical messenger within the mind, and drive up the coronary heart fee and acid manufacturing within the abdomen, in accordance with the Nationwide Most cancers Institute.
Total, between mid-March 2020 and mid-July 2021, Survivor Corps members talked about utilizing antihistamines on the group’s Fb web page greater than 900 occasions, Lambert and her colleagues calculated. To realize extra perception into these anecdotal studies, the crew determined to zoom in on two Survivors’ accounts.
The primary affected person possible turned contaminated with COVID-19 in early January 2020, earlier than diagnostic assessments would have been out there, the researchers reported. Throughout her preliminary sickness, she developed profound fatigue, fever, dry cough, chest ache, ulcers in her mouth and pores and skin rashes on her torso, amongst different signs. Most of those signs resolved inside 24 days, however some, just like the rashes and chest ache, continued.
Over the next weeks and months, new signs started to emerge, together with cognitive impairment and pinpoint bruising on the arms, legs and trunk. As well as, numerous signs that had beforehand disappeared returned in waves because the months wore on. In June 2020, about six months after her preliminary sickness, the affected person ate cheese, to which she has a identified allergy. She promptly took the over-the-counter antihistamine Benadryl (diphenhydramine) to stave off an allergic response.
“So she didn’t take this pondering, ‘Oh, I am taking this for lengthy COVID signs.’ Like she was by no means anticipating to get up and really feel higher,” mentioned Melissa Pinto, first creator of the brand new case report and an affiliate professor of nursing at College of California, Irvine. Nonetheless, the subsequent day, the affected person seen she felt considerably much less fatigued and higher in a position to focus than the day earlier than. These optimistic results wore off over the next three days, so she tried taking Benadryl once more. Once more, her signs improved, and she or he continued taking the drug every day for the subsequent six months.
One in all her medical suppliers then prescribed Vistaril (hydroxyzine pamoate), a stronger antihistamine that is additionally used as an anti-anxiety medicine. On a every day dose of the drug, “the affected person had an almost full decision of train intolerance, chest ache, fatigue, and mind fog,” and her bruises, complications and rashes steadily improved over time, the case report notes. After 9 months of remedy, she’d regained about 90% of her pre-PASC functioning, and she or he was in a position to absolutely return to work and repeatedly train, as she had previous to her an infection.
The second affected person within the case report shared an analogous story. She’d possible caught COVID-19 in March 2020, Pinto mentioned. On the time, she examined damaging for SARS-CoV-2 on a PCR take a look at, however she then developed chills, shortness of breath and chest ache, and she or he obtained a medical prognosis of COVID-19 primarily based on these signs. The affected person went on to develop fever, joint ache and shortness of breath, in addition to speedy coronary heart fee, issue concentrating, belly ache, style and odor loss and distinct rashes on her toes, often called “COVID toes.”
Previous to catching COVID-19, the affected person had seasonal allergic reactions that she handled with Allegra (fexofenadine), a non-drowsy antihistamine. Someday, she ran out of Allegra and used Benadryl as a substitute. As an older, first-generation antihistamine, Benadryl can block histamines from plugging into receptors within the the mind; histamines assist to control sleep and wakefulness, and by blocking this exercise, Benadryl could cause drowsiness, Dwell Science beforehand reported.
Nonetheless, after taking the drug, the affected person seen a marked enchancment in her mind fog and total fatigue. She started taking Benadryl every day and famous continued enchancment in these signs; her belly ache additionally subsided and her senses of style and odor returned. She now takes Benadryl within the night and Allegra within the morning, and on this routine, she’s regained about 95% of her pre-PASC functioning, the case report notes.
Extra help for antihistamines
The small case report shouldn’t be generalized throughout all folks with lengthy COVID, Pinto emphasised. “This isn’t to be extrapolated as, ‘This may assist everybody,'” she mentioned. Fairly, she mentioned she hopes the case report serves as a jumping-off level for additional analysis and for conversations between different lengthy COVID sufferers and their medical suppliers, as they seek for potential options.
“The great factor in regards to the antihistamines is there’s little or no draw back,” because the medicines are secure, low-cost and trigger few unwanted effects, Dr. Paul Glynne, the medical director of The Doctor’s Clinic in London, a guide doctor at College School London Hospitals, and first creator of the Journal of Investigative Drugs (JIM) report. For many lengthy COVID sufferers, “I am unable to see a superb purpose to not begin antihistamines,” he mentioned.
(That mentioned, the long-term use of some antihistamines has been linked to an elevated threat of dementia, notably in older folks, in accordance with The New York Occasions.)
After publishing their JIM report, Glynne and his colleagues started providing all their lengthy COVID sufferers antihistamines and have now handled upwards of 200 further sufferers utilizing an ordinary protocol, Glynne mentioned. The sufferers take a mix of H1 blockers and H2 blockers; typically, H1 blockers are prescribed for irritation and different allergy signs, and H2 blockers are prescribed to scale back the quantity of acid produced by abdomen cells.
Roughly 65% to 70% of their lengthy COVID sufferers reply nicely to the remedy and have a tendency to see enchancment in particular signs first, specifically, their pores and skin rashes and gastrointestinal points, Glynne mentioned. Different signs, resembling mind fog and fatigue, typically take longer to enhance, on the order of weeks.
This delayed response hints that, along with blunting the consequences of histamine, the remedy could set off different downstream results within the immune system, Glynne mentioned. For instance, some research trace that T cells — white blood cells that defend the physique in opposition to pathogens — turn into dysfunctional in lengthy COVID. These cells carry each H1 and H2 receptors that antihistamines can block, though extra analysis is required to determine precisely how the medicine may have an effect on the cells’ operate, the JIM report notes.
After which there’s the matter of mast cells, Afrin mentioned. There’s a big diploma of overlap between the signs reported by lengthy COVID sufferers and people seen in folks with mast cell activation syndrome (MCAS), a illness the place a number of the mast cells turn into faulty and spew too many chemical brokers. It is attainable that “uncontrolled, aberrant mast cells” underlie no less than a number of the pathology of lengthy COVID, Afrin and his colleagues proposed in a 2021 report within the Worldwide Journal of Infectious Ailments. Antihistamines could assist to reign in a few of this unbridled exercise — however for now, that is only a speculation, Afrin mentioned.
Rather more analysis will likely be wanted to pin down precisely how antihistamines assist lengthy COVID sufferers. Whereas that is ongoing, although, the easy-to-access medicine may supply some sufferers aid, now, Pinto mentioned. “Whereas all these different greater questions are being explored, we’ve got to consider getting sufferers again on their toes,” she instructed Dwell Science. Those that are keen on making an attempt the remedy ought to first seek the advice of a medical supplier about potential dangers and drug interactions, she harassed.
“It is about making an attempt to get these folks functioning to a degree that they will get again to their lives, get again to work, get again to train, with out risking a recurrent flare of their post-viral sickness,” Glynne mentioned, echoing the sentiment. A few of his personal sufferers have improved to the purpose that they have been in a position to cease taking antihistamines, though most nonetheless take the medicines every day, he mentioned.
Afrin, Glynne and Pinto all agree that, though antihistamines appear useful for some lengthy COVID sufferers, they’re unlikely to assist all long-haulers. Glynne mentioned that roughly 10% to twenty% of his sufferers do not reply to the remedy in any respect, and even in sufferers that reply nicely, not all their signs essentially enhance. Specifically, dysautonomia, or dysfunction of the autonomic nervous system that controls involuntary actions, like coronary heart beat, doesn’t appear to enhance with antihistamines, he mentioned.
“[The treatment] actually is a part of a form of wider package deal of measures,” Glynne mentioned. “I do not assume there’s going to be one single pathway that you just block or goal that is going to easily deal with what is clearly a fancy downside.”
Initially revealed on Dwell Science.