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Comment by ndsipa_pomu | Hacker News Reader

I'm currently taking 10,000IU per day in an effort to control psoriasis, but it's a bit of guess work really and trying stuff to see what helps. It's somewhat annoying that I've had a dermatologist order some blood tests, but they were only targeted for whether I can safely take acitretin (a retinoid). I wish there were cheap home-tests for various blood levels of minerals and vitamins like there are for things like glucose and uric acid (I occasionally get gout if I eat too much oily fish or asparagus).

Edit: just found that there are ones for vitamin d - shame there don't seem to be calcium ones.

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We don't really have evidence that vitamin D supplementation has any effect on psoriasis. This large review and meta-analysis from 2023 by Formisano et al [1] is a very good paper on the subject.

It's true that studies regularly show that vitamin D deficiency correlates with psoriasis disease severity, at least when it comes to plaque psoriasis. But when patients are given vitamin D to normalize levels, their psoriasis tends not does not improve. (We have a tiny handful of studies that do show improvement in symptoms, but they are small and of poor quality.)

It may be that severe psoriasis simply causes vitamin D deficiency, e.g. by disrupting the skin's ability to synthesize vitamin D (which normally builds up and is released upon exposure to sunlight), rather than vitamin D deficiency causing psoriasis. There's at least one study that shows that people with psoriasis tend to avoid the sun more than other people.

[1] https://www.mdpi.com/2072-6643/15/15/3387

One of the problems with psoriasis is that it seems to behave differently for different people and also changes over time too which makes it very much a case of trial and error to find what treatments work for people.

There's definitely a link between psoriasis and vitamin D, but as you state, it's not necessarily a deficiency that triggers it. However, anecdotally there's people who do benefit from taking vitamin D3 (along with K2 seems to be a popular combo) so I think it's worth a shot though I have tried it in the past without much success (that wasn't erythrodermic psoriasis though).

I've definitely noticed that sun exposure does help with plaque psoriasis and most people will see that their condition worsens over winter - that may be due to lower sunlight levels or cold, dry air exacerbating skin issues. And yes, psoriasis does affect people's self-image, so it can be embarrassing to expose skin when it looks like you've got some kind of plague.

True, and I would never go as far as saying that the benefits have been disproven.

I do hear about many people trying to treat their psoriasis wit vitamin D, but not about many success stories.

As far as we know, the reason sunlight helps psoriasis is not vitamin D, but because UVB at specific wavelengths has an immunosuppressive effect on the skin. It induces apoptosis of T-cells and promotes keratinocyte differentiation.

> I do hear about many people trying to treat their psoriasis wit vitamin D, but not about many success stories.

It seems to my non-expert opinion that it's a piece of the puzzle, but there's a lot more other pieces. It seems to be often linked with selenium deficiency and I've read one case of a really bad erythrodermic patient that was treated with calcium.

I successfully treated my eczema with Vitamin D. It did take several months to clear up, but now I can eat what I want with no risk of a flare-up. I took 5000IU daily. I still take it now, but only a couple of times a week.

It doesn't work for all cases of eczema or psoriasis, unfortunately; many people I have recommended it to did not have the same response.

Best of luck - I hope your Vitamin D experiment works out for you!

Taking vitamin D daily did wonders for my psoriasis. Over the years it had gotten to the point where I was breaking out in patches all over my body, and only getting worse as time went on. I went from like 2% coverage to 20%.

Started taking vitamin D and am now back at 2% (where it has sat for 4 years now since I started).

That's what I'm hoping for.

I had an outbreak of erythrodermic psoriasis (usually just have mild plaque psoriasis) over the winter and had it all over my trunk, arms and legs - approx 80% coverage. Luckily it wasn't as severe as it could be (no hospitalisation necessary), but I had a lot of trouble with body heat regulation for a while.

I ended up using topical steroids which cleared it up remarkably quickly, but am now trying to reduce my usage of that (stopping steroids can be a trigger for erythrodermic psoriasis) which has led to it becoming more pronounced again.

Does more exposure to sunlight help? I remember there’s UV light treatment that shines for a few minutes.

It's useful for normal plaque psoriasis, but I'm currently recovering from an erythrodermic psoriasis episode and UV light is not recommended for that. Psoriasis can be a tricky condition, as too much UV light (i.e. sunburn) can trigger it - UV therapy usually has to be carefully controlled.

Light therapy is very effective, but not because of vitamin D. UVB light has an immunosuppressant effect on the skin.

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