My daughter has been consulting a doctor at a private allergy clinic. Her Genova complete parasitology stool test results have come back and she has a parasitic infection called Dientamoeba Fragilis and little or no beneficial Lactobacillus or Bifidobacteria. This parasite apparently causes malabsorption leading to a wide variety of symptoms including chronic fatigue, IBS, food sensitivities, bloating, depression, hair loss and painful joints. It damages the gut lining and is associated with inflammatory bowel disease and Crohns. It thrives on carbohydrates so this may explain why my daughter's health has improved somewhat on a low carb diet.
She also had a Biolab urine test which shows very low iodine (possibly as a result of malabsorption issues caused by parasitic infection?) which may explain the symptoms of hypothyroidism.
We're seeing the allergy doctor again this week so will report back on what treatment is recommended. Thought this info might help others with similar symptoms.
Very frustrated that my daughter has been struggling with poor health for the past 18 months, and despite having all the above symptoms, all requests to our GP for stool testing have been refused and the only treatment that has been offered is antidepressants. It's scandalous really.
Fingers crossed that these results will lead to successful treatment. Thanks to everyone here who has helped us get to this point in our journey.