What are flare ups?
I want to begin with:
Every body, every single one of them is extremely different. Flare ups are subjective not objective. What one chronically ill person experiences is and will be completely different from what another chronically ill person experiences. It does not matter if they have the same/same combination of chronic illnesses.
To understand what flare ups are we need to first understand what a chronic illness is, or what chronic pain means. Let's tackle that first.
What is a chronic illness? What is chronic pain?
Chronic illnesses/diseases are illnesses/diseases that generally last for a minimum of 1 year (this time duration is specific to the medical institution that you refer to, I have referred to CDC for the time duration I have mentioned above), they require ongoing medical attention, and/or limit activities and/or daily living.
Chronic pain can occur anywhere in the body, sometimes it might have a physiological cause which can be remedied, sometimes the remedy/treatment might not work and the person in chronic pain will still experience pain. The best course of action then is a combination of medication, therapy and lifestyle changes.
Chronic pain can be persistent and constant or pain that comes and goes. The time frame that is required to term any type of specific pain as chronic pain is again subjective to the medical institution that you might be referring to; for the topic of chronic pain I have referred to Cleveland clinic.
Now coming to overarching question:
What are flare ups?
A flare up is a duration of time when a chronically ill person or a chronically in pain person feels all their symptoms acutely, in a heightened form. All of their symptoms are worsened. Flare ups generally get better after an unknown amount of time, it is temporary, however flare ups can last for days, weeks or an entire month or more sometimes.
What might flare ups feel like?
Flare ups are different for every person. As said in the very beginning of this article, chronic illness and chronic pain are subjective to that specific body irrespective of two people having the same chronic illnesses/combination of illnesses.
I have Type III Achalasia Cardia, Scoliosis and Migraine. My flare ups generally consist of severe oesophageal spasms, not being able to swallow, it feels like the door to my stomach is closed shut which it is because in achalasia the LES, Lower Oesophageal Sphincter, is in a constant state of contraction. My back pain increases when I do not eat which is what happens when my achalasia flare ups happen. I end up with back pain that is not localised to the curvature area which is generally the depth of my pain. I feel it all over my back and head aches. I feel two different types of headaches, one is a headache that is caused due to the curvature of my spine, that is a headache that is constant, I get up with it, go through the day with it, sleep with it, the other type of head ache is a migraine. During achalasia flare ups, if it is a simple oesophageal spasm it, it is a raging forest fire in my chest. If it is accompanied with me not being able to swallow which can last from one day to sometimes an entire week or more, I end up with a lot of other types of pain.
I have done a very bad job at explaining it, but I hope I have given you a glimpse into what it might feel like
What can flare ups look like?
Sometimes flare ups are visible, most of the time flare ups might not be visible.
