POIS is most likely a mast cell activation disorder.
Mast cells are primitive cells of the immune system which act as “sentinels,” present in all tissues but standing guard most prominently at the body's environmental interfaces, e.g. the skin, the gastrointestinal tract, the respiratory tract and the genitourinary tract. Unlike lymphocytes, which have great specificity, mast cells use non-specific chemical mediators as their dominant mechanism of attack against foreign invaders (e.g. parasites). More than 200 different mast cell mediators have been identified, including histamine, tryptase, heparin, prostaglandins and leukotrienes.
Unlike allergies, which involve specific IgE-mediated activation of mast cells, mast cells in MCAS are activated inappropriately by specific and non-specific triggers, such as positive or negative emotional or physical stress, extremes of temperature or temperature or barometric pressure change, environmental chemicals, alcohol, high histamine foods, odors, physical stimuli (e.g. pressure from a tourniquet), drugs, and the non-drug ingredients (excipients) in medication products. Since mast cells are present in all organs, and since their chemical mediators enter the bloodstream, inappropriate mast cell activation can produce a large number of signs and symptoms that may vary and occur in a fluctuating pattern, often creating a complex clinical picture. Like most diseases, MCAS exists on a spectrum, ranging from very mild to extremely severe, and it has been estimated to affect up to 17% of the population.
Symptoms of MCAS may be acute and/or chronic. Skin flushing, itching, fleeting rashes and hives are very common, but not all patients have grossly obvious cutaneous manifestations. Other common symptoms include bone, muscle, joint and/or neuropathic pain; paresthesias; gastroesophageal reflux; abdominal pain; nausea/vomiting; bowel motility issues (gastroparesis and/or diarrhea alternating with constipation), presyncope/syncope, heart rate and/or blood pressure lability, chest pain, dyspnea (often subtle, typically described as an occasional brief inability to take a deep breath), unexplained weight loss or gain (which may be significant), anxiety, depression, mood lability, cognitive dysfunction, sleep disturbance, lethargy, fatigue, malaise, fevers, night sweats, headache and vertigo. Many patients experience mast cell “flares” or “spells,” but more severely affected patients also have chronic symptoms due to constitutive mediator release aside from mediator release related to aberrant reactivity. Prior to adulthood, patients with MCAS often initially enjoy symptom-free intervals interspersed amongst symptomatic periods. Over time, symptom-free intervals shorten, and finally symptoms become chronic with an intensity which fluctuates, but with an overall trend toward steadily increasing severity. An increase in disease severity often follows major stress. Mast cells are also intimately involved in growth regulation.
Patients with MCAS have often experienced a lifetime of multi-system unwellness with broad themes of inflammation, allergy, and disordered growth. For most MCAS patients, signs of the disease first emerge in childhood (median age at symptom onset is 9 years), but there is an average delay in diagnosis of MCAS of 30 years In one evolving model, MCAS increasingly is being suspected to arise proximately from mutations in one or more mast cell regulatory genes, and these mutations – usually somatic, heterozygous, and multiple – themselves likely emerge due to complex interactions among other mutations which are germline (i.e., inborn) and both genetic and epigenetic6, 7. Stressor-induced cytokine storms, too, may significantly impact these interactions and the development of the consequent somatic mutations (that is, mutations which are acquired, not inborn, but often beginning relatively early in life). MCAS may also occur secondary to an underlying allergic, infectious, immunodeficiency or an autoimmune disorder.
Most of the pois treatment prepacks work largely by blocking the mast cell activaton or histamine release.
Niacin
http://getwellstaywellathome.com/blog/2015/06/seasonal-allergies-and-the-niacin-flush/Taurine
https://www.ncbi.nlm.nih.gov/pubmed/28694089TRT
https://journals.aace.com/doi/pdf/10.4158/EP161530.CRRelief with Antihistamines, flavanoids in fenugreek&garlic, oral corticosteroids ,methylation support,pre-pack with IDO/TDO/NMDAr blockers+ anti-oxidants and gluten free diet etc all point to mast cell activation disorder.
Most of our members get relief with one of the above mentioned ways which also fits with MCAD where everyone has individual triggers and get relief with personalised treatment.
So POIS is most likely to be MCAD triggered by mast cells present in the urinary tract and causing systemic inflammation which many a time crosses blood brain barrier and results in neural inflammation.