Nightshade allergy

I had an interesting query from a local GP today: "What HRT options are available for a patient with a Nightshade allergy?"

We chatted for a while and it turned out I had about a week to get to the bottom of this. We both knew this was not a normal query, so that was a relief.

Ok, first things first, what is a nightshade? I had heard of nightshade- a plant used in fictional stories to make potions- but never imagined it was a real plant, or rather, family of plants. A second thread to this question I had come across when my brother was studying agricultural science and he told me that tomatoes, eggplants and potatoes were all part of the same plant family. Sewing the two threads together now: Nightshades are the family of plants that includes tomatoes, potatoes, bella dona, tobacco, eggplants and peppers.

So that's a Nightshade. But most of those are all very common foodstuffs. An allergy would mean no more chips and tomato ketchup! But this is the case. I must admit to initial skepticism when I first heard this patient forewarning of their allergy. In healthcare we often see an accidental or deliberate blurring of the lines between allergy and sensitivity. Perhaps people believe that healthcare professionals would not take seriously that which is only called a "sensitivity" because by definition it is less serious than a full allergy. But I can assure anyone reading this that that is not the case. Sensitivies are serous and healthcare professionals will treat sensitivities as such.

But I digress- Nightshade allergies are commonly caused by a family of organic molecules produced by nightshade plants called alkaloids. These include nicotine found in tobacco, solanine found in green potatoes and atropine found in bella dona. You may have heard of the negative health affects of these compounds. Nightshade plants produce these potentially poisonous compounds to fight off moulds, fungi and other infections that might stop the plant growing. Virtually all nightshades have some level of these compounds and individuals with allergies are particularly sensitive to these, even to levels of alkaloids found in edible plants like potatoes.

So I researched the most prevalent HRT products seen from this GP's practice as these would be the most likely first choices. I did this by reading through the SPC for each product and doing any necessary follow-up research on particular excipients. I found no prescription medicine to contian alkaloids or even starch which is commonly used as a filler in the pharmaceutical industry and can be sourced from potatoes. (Products searched included Evorel, Evorel Conti, Utrogest, Oestrogel, Lenzetto, Divigel & Vagifem)

So I was quite happy to recommend that these products could all be recommended until some additional reading showed that a sensitivity to salicylates often overlaps with nightshade allergy. This is a sensitivity to another group of molecules called salicylates, the most famous of which is Aspirin (acetylsalicylic acid). A re-check of the previous SPCs showed octisalate in Lenzetto and trolamine salicylate in both Oestrogel and Divigel.

In the end my advice to the GP was to use a combination of both Evorel and Evorel Conti to give a cyclical HRT regime or regular Evorel and utrogest, the former of which the GP had suggested as an initial plan from the outset. So my little rabbit hole didn't lead to any major new revalations or treatment plans but it did provide confidence that the current path forward was on sound footing.