Of unknown cause?

Ripples in a lake

Idiopathic is a term used by doctors to describe any symptom of which the cause is unknown. E.g. idiopathic urticaria – to us would mean hives (itchy swollen rash), that occurs for no known reason.

However, it is important not to conflate ‘of unknown cause’ with ‘with no cause’.

Not yet identified

Idiopathic just implies that the actual cause has not been identified – not that it never existed. Like the ripples in the picture above, just because we can’t see the stone that was dropped in the water, doesn’t mean it wasn’t there.

The other thing to bear in mind is that a single cause may be hard to pinpoint.

Though various environmental factors may be a trigger in this case (such as a new washing powder or eating eggs when you’re allergic), it could also be that you are being triggered by multiple factors on different days, or that you are being triggered by things that you may not be aware of, like mould or food processing aids or EMFs.

Stress, medications, exercise and physical stimuli (e.g. cold or touch) can also set off urticaria.

Immune system activation

There are also the ‘causes’ that arise from the immune system itself. Why are you less able to tolerate what might be seemingly innocuous factors in the first place?

As histamine is responsible for causing the skin weals, anything that increases inflammation (which stimulates the release of histamine) could be playing a role in idiopathic urticaria. For example underlying autoimmunity, or infection.

This explains then why low vitamin D is a risk factor for urticaria – as it is hugely important in regulating immune function, and autoimmune hypothyroidism is also associated  (1)

Similarly, if you have trouble breaking histamine down, you might be more affected. Deficiency in key nutrients needed in histamine breakdown, or issues with the health of your gut – where one of the enzymes responsible for histamine breakdown resides – could be playing a role here.

Some people with chronic spontaneous urticaria actually have an autoimmune response to the antibodies responsible for allergic reactions – so their autoimmunity stimulates the cells responsible for allergy, leading to the release of histamine (2)

In the cases where autoimmunity is playing a role, then looking at what factors are responsible for your body being able to lose tolerance to itself is important. This is where I use my framework for immune harmony to help me work through all the possibilities.

Detective work

A friend of mine, also a nutritional therapist, described herself as a medical detective the other day, and I would tend to agree with that description. Idiopathic isn’t a word that sits easily with us – we are always looking for underlying causes… either antecedents (things that have happened in the past that made you more likely to get your symptoms), triggers (things that have kicked off this particular attack of symptoms), and mediators (underlying imbalances that are contributing to your condition).

If you are interested in finding more out about what factors could be contributing to your symptoms – then do consider working with me. If you want to have a quick chat about what’s involved and how I could help, then do get in touch.



  1. Cornillier, H. et al., (2018) ‘Chronic spontaneous urticaria in children – a systematic review on interventions and comorbidities’ Pediatr Allergy Immunol 29(3): 303-310 doi: 1111/pai.12870
  2. Asero et al., (2020) ‘Co-occurrence of IgE and IgG autoantibodies in patients with chronic spontaneous urticaria’ Clin Exp Immunol 200(3) 242-249 doi: 10.1111/cei.13428

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