Here’s how the miracle happened. It’s such a totally cool miracle, it’s got scientific references…(see end of post)
1. J, wife of friend and newly trained nutritional therapist, persuades sceptical, grumpy Anna (who is pretty ill at this point) to write out a detailed medical history, describe all the treatments she’s tried, muster the results of all the tests she’s paid for over the years, list all the pills she’s taking, and keep a food diary.
2. Anna does all this, thinking: “Well, you can have a go, my dear, but I’ll eat my hat if you get anywhere.”
3. J reviews case and researches in medical and scientific journals. Comes up with hypothesis: massive build-up of histamine plus rampant histamine intolerance. She sends Anna some interesting papers including:Joneja and Carmona-Silva, Outcome of a Histamine-restricted Diet Based on Chart Audit, Journal of Nutritional and Environmental Medicine (2001) ll, 249-262. (People with various skin conditions whose symptoms had resisted previous treatment improved on low histamine-diet).

Oksarharju et al, Probiotic Lactobacillus rhamnosus downregulates FCERS and HRH4 expression in human mast cells, World Journal of Gastroenterology 2011, Feb 14; 17(6); 750-759. (Certain probiotic bacteria might diminish mast cell allergy-related activation.)

Histamine potential of foods and additives, Schweitzerische Interessengemeinschaft Histamin-Intoleranz (SIGHI),http://www.mastzellaktivierung.info/downloads/foodlist/21_FoodList_EN_alphabetic_withCateg.pdf

4. Anna, who’s already noticed that foods like sauerkraut and smoked salmon make her worse, goes on a strict low histamine diet, avoiding aged, preserved, canned and processed foods, plus specific foods like tomatoes which are naturally high in histamine and/or provoke the release of histamine by the body.Light sensitivity improves slightly.
5.Anna swaps standard probiotic for probiotics which actively increase DAO – histamine-reducing enzyme – in the gut(1)(2). Starts with Lactobacillus rhamnosus – light sensitivity improves. Adds in Bifidobacterium infantis – light sensitivity improves more.  Adds in Lactobacillus salivarius – light sensitivity improves further (probiotic powders from http://www.metabolics.com).
6.Essential Fatty Acid blood test shows deficiency in delta-6-desaturase(3), the enzyme needed to convert linoleic acid to gamma-linoleic acid (GLA). Anna takes borage oil which supplements GLA directly. Skin improves more.
7.DNA profile shows gene mutations(4)  suggesting Anna has problems making a compound called SAMe (5) (part of the methylation cycle), necessary to degrade intracellular histamine(6). Anna eats more choline-rich foods(7) , takes hydroxy B12(8)  and phosphatidyl choline supplements which all support SAMe production(9).  Light sensitivity improves further.
8.Second, more comprehensive DNA profile (from https://www.23andme.com) shows mutations on yet more genes involved in extracellular histamine degradation(10), confirming importance of assisting key parts of the methylation cycle to compensate. Anna also has mutations (on MAO A genes) that may interfere with degradation of biogenic amines, histamine being one of these. Anna starts B2 supplements to support MAO mutations.Light sensitivity improves further.

In June 2016, Anna, wearing a large hat and under a tree, sits in the garden on a sunny afternoon, FOR THE FIRST TIME IN TEN YEARS.

References

1. Kukkonen K, Savilahti E, Haahtela T, Juntunen-Backman K, Korpela R, Poussa T,Tuure T, Kuitunen M (2007) Probiotics and prebiotic galacto-oligosaccharides in the prevention of allergic diseases: a randomised double-blind placebo-controlled trial. Journal of Allergy and Clinical Immunology 119:192-8
2. Mizuguchi D, Das H, Matsushita AK, Maeyama C, Umehara K, Ohtoshi T, Kojima J, Nishida K,Takahashi K,Fukui, H (2008). Suppression of histamine signaling by probiotic Lac-B: a possiblemechanism of its anti-allergic effect. Journal of Pharmacological Sciences, 107:159-166.
3. Tollesson A, Frithz A, Berg A, Karlman G (1993) Essential fatty acids in infantile seborrheic dermatitis. Journal of the American Academy of Dermatology, 28: 957-961.
4. Preuss CV, Wood TC, Szumlanski CL, Raftogianis RB, Otterness DM, Girard B, Scott MC,Weinshilboum RM (1998) Human histamine n-methyltransferase pharmacogenetics: common genetic polymorphisms that alter activity. Molecular Pharmacology, 53:708-17.
5. Barbosa PR, Stabler SP, Machado ALK, Braga RC, Hirata RDC, Hirata MH, Sampaio-Neto LF, Allen RH, Guerra-Shinohara EM (2007) Association between decreased vitamin levels and MTHFR, MTR and MTRR gene polymorphisms as determinants for elevated total homocysteine concentrations in pregnant women. European Journal of Clinical Nutrition, 62:1010–1021.
6. Lewis CA (2015) Enteroimmunology: a guide to the prevention and treatment of chronic inflammatory disease. Carrabelle, Florida: Psy Press.
7. McGuire M, Beerman KA (2015) 3rd Edn. Nutritional sciences:from fundamentals to food. Belmont, California: Wadsworth, Cengage Learning.
8. Bolander-Gouaille C (2002) 2nd Edn. Focus on homocysteine and the vitamins involved in its metabolism: France:Springer.
9. Zeisel SH (2006) Choline: Critical role during fetal development and dietary requirements in adults. Annual Review of Nutrition, 26: 229-250.
10. Mitchell ES, Conus N, Kaput J (2014) B vitamin polymorphisms and behavior: Evidence of associations with neurodevelopment, depression, schizophrenia, bipolar disorder and cognitive decline. Neuroscience & Biobehavioral Reviews, 47: 307–320.