In the strictest terms, a "noxious stimulus" is something that produces pain. For purposes of this discussion, these are the things that seem to set off or intensify some people’s symptoms.
There are the well-known and fairly common noxious stimuli of hot weather and infections in people with MS, which can cause us to have all sorts of symptoms and pseudoexacerbations. Other common noxious stimuli:
Stress can cause fatigue to worsen
Cold can increase spasticity
Constipation can also increase spasticity
I have also have heard of people having more unusual reactions to things, such as:
Peppermint candy increased one woman's trigeminal neuralgia
Being hungry or thirsty make some people more prone to the "MS hug"
Clothes that itch or bind can set of spasticity
Eating sugar can make tingling in the feet (paresthesia) more noticeable
For myself, I know that if one of my daughters sits on my lap in the wrong way, I am more likely to feel the MS hug. I also know that the chlorine and the loud noises at the indoor pool where my girls take swimming lessons give me a mini-migraine and incredible fatigue. If I have to concentrate really hard on a social situation, such as following a complex conversation, I am also wiped out to the point of feeling nauseated. Strangely, I also notice that many of my sensory symptoms get much worse during a lightening storm.
This is something that docs may not be that interested in discussing with you. Mine aren't. It is important to understand that most of our symptoms just happen without any reason. However, there may be certain MS symptoms that are made worse by exposure to our own personal noxious stimuli, which don't necessarily affect others in the same way.
Think about it for a moment in terms of your own symptoms. Is there a time of day when you tend to feel a certain symptom more than other times? What are you usually doing when you are bothered most by this symptom? Is there a certain activity or environment that this symptom could be linked to?
Maybe the answer is "no"–you simply cannot link your symptoms to anything external. Take some time over the next few days and observe carefully. Maybe you will see a link.
On the other hand, perhaps this post resonates with you. For instance, once you really start thinking about it, you may realize that your legs do feel a little more tingly after you talk to your boss about a difficult issue or your balance is off if you miss breakfast.
It's great to recognize these things, but what can you do? Clearly, if we could avoid all of the things that made us feel worse, that would be ideal. However, there are many situations that are an unavoidable part of our lives at the moment. Here are some options:
Minimize exposure to noxious stimuli: Clearly, if eating a certain thing makes you feel worse, it is usually easy to avoid eating it (especially if it is something that is not a common ingredient in many foods). If you find that interacting with a certain person brings on MS-related discomforts, limit necessary communications to email as much as possible. For my problems at the pool, I can watch my daughters' lessons through the large windows by the pool, rather than in the bleachers.
Plan for aftereffects: If your symptoms feel worse after doing something that you cannot avoid, then have a plan for trying to recover from them (or at least returning to baseline). For instance, if driving home in traffic brings on tingling in your feet, make sure that you have at least 15 or 20 minutes to do something that you love when you get home (reading a book with a cup of tea, listening to music, doing a crossword puzzle) before you jump into making dinner.
Bottom line is that you are probably right if you think that exposure to a certain thing or situation makes you feel worse. Avoid these things for awhile if possible and see if your suspicions are confirmed.
What about you? What do you think makes certain symptoms act up? Have you changed anything to avoid these noxious stimuli? What was the result? Share your story with us here.