Key takeaways.

  • Can a penicillin allergy also cause a mushroom allergy?

    There's not much evidence that penicillin allergies cause cross-reactivities with other moulds or fungi, so it's still considered unlikely that a penicillin allergy would be related to a mushroom allergy.

  • Is it safe to have magic mushrooms if you have a penicillin allergy?

    If your allergy to penicillin is mild (it doesn't cause hospitalization), then it is still safe to try magic mushrooms. But if you have strong allergies to penicillin or to other mushroom varieties, it may not be safe.

  • Tips for trying magic mushroom safely if you have a penicillin allergy?

    Have a tripsitter (who isn't taking mushrooms), start with only a small dose, keep antihistamines around, and don't freak out at small reactions such as skin hives. Call emergency services if the allergy becomes an emergency.

We’ve received a number of questions regarding the use of magic mushrooms and penicillin allergies. It’s a valid question given that penicillin is a form of mould and magic mushrooms are a form of fungus — the two kinds of organisms are very similar. And there are many wondering whether or not it’s safe to use magic mushrooms if you also happen to have an allergy to penicillin.

We’ve got a very interesting topic on our hands because there are a few different kinds of sensitivities that can manifest between humans and fungi. There’s mushroom allergies which are vague and nonspecific, penicillin allergies which are specific to penicillin but not all kinds of fungi, and then there’s other specific mushroom allergies. But where do these allergies overlap?

It’s important to remember that magic mushrooms do not contain penicillin. Which means that a person with a penicillin allergy will not necessarily have an allergy to magic mushrooms. But that doesn’t mean there isn't something else in the mushroom that the person could have an allergic reaction to. This is an especially important factor to consider in those with overall mushroom allergies.

In this article, we’re investigating the difference between different mold allergies and sensitivities, and how someone with a penicillin allergy might safely go about using magic mushrooms.

Penicillin allergies, mushroom allergies, and mold sensitivities.

A painting of psychedelic magic mushrooms in outerspace surrounded by asteroids with faces on them.

Penicillin is a kind of fungus or mould that happens to be beneficial to the human body — just like magic mushrooms! When you think about it, there are a number of different fungi that humans have come to love. Even the good ol’ button mushroom is a healthy fungus for humans.

However, just like with many other foods, there are a small group of people for whom fungi trigger different kinds of allergies. Penicillin allergy is considered the most common worldwide allergy, with around 8-12% of the population having a sensitivity reaction of varying degrees to penicillin. 

That being said, it’s uncommon for there to be penicillin cross-reactivity with other molds, even if they are respiratory ones. That’s to say — just because a person is allergic to penicillin doesn’t mean they’ll have an allergic reaction to mushrooms, moulds in cheeses such as blue cheese, or Psilocybin magic mushrooms.

In the modern context “mushroom allergy” is widely accepted as an allergy to mushroom spores, with certain species being primary culprits. However, it’s primarily a respiratory reaction and isn’t thought to occur by eating magic mushrooms. Once upon a time, though, there was some scientific mention of non-specific mushroom allergies.

There have been reported reactions of gastrointestinal symptoms after oral ingestion of shiitake mushrooms and even reports of contact dermatitis after eating raw shiitake mushrooms. It seems from the research and anecdotal reports on forums such as Reddit that allergies to wild mushrooms or edible mushrooms manifest as itching, redness, hives, rash, and in the worst cases, anaphylaxis. 

Mushrooms are all composed of different things, all of which could theoretically cause an allergic reaction if the person has an allergy to any of those compounds. It’s worth noting that what makes psilocybin mushrooms “poisonous” is psilocybin itself! And if you’ve ever used magic mushrooms, you know what “magic mushroom poisoning” feels like!

So is it possible to be allergic to magic mushrooms if you have a penicillin allergy?

The short answer is yes. It is possible. But not much more likely than anybody else having an allergy to magic mushrooms. As we just mentioned, it’s possible that some cross reactivity takes place, but this has never been established for magic mushrooms.

There is still no science to back this up, but if a person has allergies to multiple kinds of fungi such as penicillin, shiitake, and porcini, then it’s more likely that they will have an allergy to something in magic mushrooms. But if the allergy is confined to penicillin, then the chances of being allergic to magic mushrooms exist, but they’re slim.

How can you safely use magic mushrooms if you have a penicillin allergy?

An illustration of a hand with different kinds of mushrooms growing out of the fingers and through the finger tips.

Now for the million dollar question: how can you safely use magic mushrooms if you’re allergic to penicillin? If you’ve never tried magic mushrooms, then quite bluntly, you don’t know if you’re allergic to them. So before deciding if it’s safe to move along and try, ask yourself the following questions:

  • Do I ever get anaphylaxis to other foods such as nuts?
  • Do I ever have allergies to normal culinary mushrooms?
  • Is my penicillin allergy severe enough to send me to hospital?

If you answered yes to any of those questions, it might not be safe for you to eat magic mushrooms. The risk might simply be too high. 

Otherwise, if you have a penicillin allergy that’s less severe but still want to create a safer environment for trying magic mushrooms, we have the following advice:

  1. Don’t trip alone. Have a trip-sitter or someone around who isn’t taking magic mushrooms that can act in the event that you start having an allergic reaction. Make sure you give them all the information they need to be able to act if you require assistance.
  2. Start with a small dose. Think about it — don't take a whopping dose of a potential allergen. Start with 1/2g to see your initial reactions.
  3. If you’re the kind of person that uses antihistamines when you get allergies, keep antihistamines around.
  4. If you keep an epipen around, make sure you know where it is. But remember, we don’t recommend trying magic mushrooms if you get anaphylaxis to any kind of mould or penicillin.
  5. Accept the small possibility of dermatitis, rash, or itching and don’t panic. However, notify someone immediately if there are any signs of tongue, lip or throat swelling.

The difference between a sensitivity and an allergy: when is it an emergency?

A painting of a sloth hanging off vines attached to unusual looking magic mushrooms.

There are varying degrees of penicillin allergy. For example, some people experience swelling on the face or hands and feet while others might experience shortness of breath or swelling of the tongue. When a person is experiencing “sensitivity” symptoms, antihistamines are usually enough to reduce them. However, if a person is having “allergic” symptoms, they might begin to experience anaphylaxis.

Any sign of swelling of the tongue, lips, or throat is the sign of an emergency and requires emergency medical care. However, in the event that hives or skin rashes appear as a reaction to magic mushrooms, it doesn’t necessarily mean that the reaction will escalate into anaphylaxis or require emergency medical care. This is why it’s important to have a tripsitter who will be able to identify these things. 

Overall, a simple penicillin allergy does not necessarily mean that a magic mushroom allergy exists — and in fact, it’s not all that likely. But given the small possibility of the two allergies overlapping, it’s just important to be prepared. And after reading this article, you should be equipped with all the preparation arsenal you need to make it a safe first experience.

Do you have a penicillin allergy and have you tried magic mushrooms? If yes, let us know in the comments what happened when you tried magic mushrooms. Your story will help lots of people in the local mushroom-using community to understand how to use mushrooms safely!

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