Thyroid UK
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Frequent infections

Hi all,

Hope you can bear with me on this - it's a bit of a saga but would be interested if anyone else has had similar experiences?

For the past 10 years I have been ill every 6-10 weeks with what has seemed like repeated infections. I've had respiratory infections, sometimes just flu-like symptoms including headaches, stomach issues, dizziness... Sometimes lasting just a few days, or sometimes going on for a month or longer. It has always been kind of cyclic. No GP has ever got to the bottom of it apart from saying 'there are a lot of viruses going around' or basically that they don't know. At a certain stage I just gave up going to the GP's as it was pointless.

At the beginning of this year work threatened to put me on a capability procedure because of my absences, not surprising really. I do try to have the least amount of time off I can. Often just go to work feeling bad.

Anyway, to cut a long story short, I am wondering now whether the root cause of all of this has been an under-active thyroid/possibly Hashimotos. I was diagnosed with it being mildly underactive about 5 years ago and the Levo. dose has always been pretty conservative, 25mcg to 50mcg.

Any comments?

10 Replies

I think you've answered your own question, though if you've any recent lab test results people will be better able to advise on whether your current dose of levo is appropriate.

I had frequent infections for many, many years when undiagnosed and also on levo. My immunity only improved - it's still not very good - when I changed my thyroid medication. You may not need to go this far to see improvement.


That's interesting, what medication did you change to?

My latest TSH result was 5.75 - Levo. just put up to 75mcg, starting today.

I once asked a GP if under-active thyroid could cause immune issues and she said 'no' quite emphatically. I think it does.


Your GP is frighteningly ignorant.

With your TSH result, you certainly need the increase. Many people don't feel better until the TSH drops to 1 or below. Make sure your surgery does a full set of thyroid function tests in six weeks (TSH, FT4 FT3, TPO and TG antibodies), in order to monitor progress. Also, do you have any vitamin and mineral test results? Optimal nutrition is vital for thyroid function and a standard healthy diet doesn't necessarily achieve this.

After 20 years on levo (and even longer undiagnosed) I decided to see a doctor privately. He tried me on desiccated thyroid, which didn't agree with me because I couldn't convert enough T4 to T3. I was put on T3 monotherapy, and gradually climbed to quite a high dose to combat peripheral resistance to TH.

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I'm getting the full thyroid test done privately, probably in the New Year now as have given up on asking GP, I haven't got the energy to argue with them. GP will just re-test TSH in a month to see if Levo. needs to go up, meanwhile I will be doing my own research!

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Quite right, and we're here to help if you have any questions.

By the way, it isn't appropriate for your GP to use TSH, a pituitary hormone, to monitor your treatment. Only a full set of thyroid tests - especially FT3 - can help with that.


Thanks! :)

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You're welcome. :-)


For full evaluation you ideally need TSH, FT4, FT3, TT4, TPO and TG antibodies, plus vitamin D, folate, ferritin and B12 tested

Private tests are available

Medichecks Thyroid plus ultra vitamin or Blue Horizon Thyroid plus eleven are the most popular choice. DIY finger prick test or option to pay extra for private blood draw. Both companies often have money off offers.

All thyroid tests should be done as early as possible in morning and fasting and don't take Levo in the 24 hours prior to test, delay and take straight after. This gives highest TSH, lowest FT4 and most consistent results

Link about antibodies

Link about thyroid blood tests

Print this list of symptoms off, tick all that apply and take to GP

You are extremely under medicated to have TSH so high

The point of Levothyroxine is to increase dose in 25mcg steps until TSH is around one and FT4 towards top of range and FT3 at least half way in range

You are extremely likely to have very low vitamin levels as result

If you have Hashimoto's then look at strictly gluten free diet

Hashimoto's affects the gut and leads to low stomach acid and then low vitamin levels

Low vitamin levels stop Thyroid hormone working

Poor gut function can lead leaky gut (literally holes in gut wall) this can cause food intolerances. Most common by far is gluten

According to Izabella Wentz the Thyroid Pharmacist approx 5% with Hashimoto's are coeliac, but over 80% find gluten free diet helps significantly. Either due to direct gluten intolerance (no test available) or due to leaky gut and gluten causing molecular mimicry (see Amy Myers link)

But don't be surprised that GP or endo never mention gut, gluten or low vitamins. Hashimoto's is very poorly understood

Changing to a strictly gluten free diet may help reduce symptoms, help gut heal and slowly lower TPO antibodies

Meanwhile adding selenium supplements can help, plus daily vitamin C

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Thanks for the info. I've been on Omeprazole for years as well, I'm sure that doesn't help with anything gut related but when I try to wean myself off get terrible heartburn.


Yes - will add some info a bit later as out at moment

Omeprazole causes lots of problems

Usually it’s low stomach acid not high causing problems

But must Not just stop Omeprazole has to be reduced extremely slowly and other things introduced instead


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