My sister is on a JACK medicine for her ulcerative colitis but she said it may soon be used for allergies.  Is that true?

Well, kind of.  First of all, not to be too picky but there is a whole family of JAK drugs and the “JAK” refers to Janus kinase which is a pathway that transmits signals across cell membranes.  The JAK system plays important roles in embryonic development, stem cell development, blood cell production and inflammation signaling. 

This last role is why it can be targeted to prevent inflammation, because left to its own devices it transduces signals from cytokines (chemical messengers) into cells leading to inflammation.  I’m pretty sure your sister is taking tofacitinib which is also being used to treat rheumatoid arthritis and most recently Covid-19. 

You might have heard about a phenomenon in severely ill Covid patients called cytokine storm.  Basically, these particular individuals have an unbridled inflammatory response to Covid which causes the severe lung inflammation.  Tofacitinib has saved the lives of thousands of ICU hospitalized Covid patients by abrogating this “over the top” inflammation. 

But to get to the point of your question, the JAK system has great potential to help a myriad of allergic conditions.  Just as Covid related cytokine storm, and autoimmune diseases such as your sister’s rheumatoid arthritis are due to failure to properly regulate the immune system, so too is allergy. 

The currently available JAK drugs are taken orally and therefore work systemically.  Because of their systemic nature there is some potential for untoward side effects such as immune suppression.  The research on JAK’s for

allergy has focused on site delivery either by inhalation to treat asthma or by skin application to treat eczema.  Research on both of these applications is very promising.  In fact, the FDA just approved the first topical JAK for treating eczema: Opzelura (ruxolitinib cream).  For both asthma and eczema, the JAK drugs will provide an alternative to steroids to treat the inflammation that causes both conditions.