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Smoking and Psoriasis

A report on tobacco smoking and its relationship to psoriasis.

Let me begin by saying that whether or not cigarette smoking has any effects on psoriasis, it would probably be better if you quit smoking, or never start smoking. The health effects of smoking cigarettes are well-known and much more likely to do permanent harm than is psoriasis. As Jerry J. once said, “Quitting smoking is a far more important step toward future health than anything related to psoriasis.”

Also let me say that this article will not be addressing any possible effects marijuana smoking might have on psoriasis, other than to say that there have been exactly zero medical articles published examining that issue. Therefore, anyone who might claim that marijuana has some known effect on the disease process is probably wrong.

Now then, does smoking have an effect on psoriasis? The answer isn’t a simple yes or no.

One thing which is absolutely certain, however, is that no studies have been published in the major medial literature since 1965 which address the question of whether or not quitting smoking will help psoriasis. Not a one. If you are reading this looking for a more-or-less definite answer to that question, I’m afraid you’ll largely be disappointed. I was disappointed, too, but realize there may be several levels of difficulty in setting up a clinical study which might be able to answer the question. See the section “The Personal Touch,” below, for one attempt at an answer.

What do the online abstracts of medical literature say, if not the above? Well, as a whole, in the broadest view, it says that psoriasis is “associated with” smoking. Since 1994, this has been used as an assumption in some studies of psoriasis (and other skin diseases) and smoking.

But that doesn’t really mean much by itself. It certainly doesn’t mean that all smokers will develop psoriasis. Or that psoriasis will vanish when a patient quits smoking. There are plenty of non-smoking psoriatics in the world.

Surprisingly, the earliest study I found (1990) which made an attempt at testing the association found none at all.[1] This could have been due to a number of factors, including location, the fact that they were looking for alcohol associations primarily, or that it was done on men (this makes a difference, as we shall see).

I found only two other clinical studies which actually asked the general question, “is psoriasis associated with smoking?” Both were published in 1992. Mills et al[2] found that if you smoke, you were more than twice as likely to have psoriasis as the general population, and found almost four times the number of ex-smokers among psoriatics as was expected. These researchers also found that if you smoked more than a pack a day (twenty cigarettes), you’d be over five times as likely to have psoriasis as normal.

Later in 1992, Naldi et al[3] found that among people with a new diagnosis of a skin disease, smokers were twice as likely to be freshly-diagnosed with psoriasis than other diseases, if they smoked more than fifteen cigarettes a day.

Now, I can’t say that these two studies were “definitive” in any way, and I can’t find any more basic research on the general question of psoriasis and smoking (more specific studies, yes, see below). But it appears from later articles that the association between psoriasis and smoking has been fairly firmly established. Some quotes from these later abstracts:


At least one study has also found that some cancers, especially those related to smoking or alcohol, are associated with psoriasis.[10] This appears, though, to simply be more evidence that psoriatics smoke more than the general population. However, another study found that smokers who undergo PUVA have a higher occurance of a certain type of DNA damage (which might lead to cancer) than non-smokers.[11] This might point at a higher risk of cancer among smoking psoriatics using PUVA than non-smoking psoriatics using PUVA, so if you’re undergoing PUVA therapy and you smoke, you might consider speaking with your dermatologist about this.

Male/Female Differences

While it is, apparently, true that psoriatics in general smoke more than normally-skinned folk, this is, it appears, even more true of women.[12] In another study among women with psoriasis, smoking was found to be a risk factor for the disease, but smoking was not found to be associated with the severity.[13] This would indicate that smoking is a risk for bringing on the first symptoms of psoriasis, but not a factor making the disease worse, at least in women.

Two other studies speak to sexual differences in smoking as it relates to psoriasis. One says that current smoking is associated with psoriasis in women, while being an ex-smoker is associated with psoriasis in men.[14] The other study found that women who smoke were about twice as likely to be hospitalized for psoriasis as non-smoking women.[15]

Palmoplantar Pustulosis

Palmoplantar Pustulosis (PPP) is a form of pustular psoriasis localized to the hands and feet. This form of psoriasis has been very highly correlated with smoking in some studies:


Yet another study from Sweden on PPP and smoking may point towards a mechanism for the correlation. Certain types of cellular receptors are greatly affected by nicotine, and can have large effects on the functioning of the cells they reside in. In PPP patients who smoke, the normal pattern of cells in the skin which have these receptors was found to be vastly different from the pattern found in patients without PPP, even smokers without PPP. The researchers think that “there is an abnormal response to nicotine in patients with PPP,” which could result in inflammation.[20]

Coincidentally, while examining the correlation between smoking and PPP, I ran across a study which says that patients with PPP sometimes experience a reduction in bone mineral density, which could lead to osteoporosis (the researchers also state that while four times as many PPP patients smoked as did their control patients without PPP, the amount of cigarettes smoked didn’t appear to have any effect on the reduction in bone mineral density).[21]

The Personal Touch

In what amounts to a very basic retroactive “poll” of psoriatics, I combed the Google archives of the psoriasis newsgroup to find out whether psoriatics themselves had any ideas about smoking and the disease, like whether or not quitting smoking would help eliminate psoriasis. After skimming perhaps 600 posts from the last seven years, I was able to fit 91 people into five broad categories:


It should be obvious at a glance that just about half of the people I could categorize fall into the “makes no difference” camp. The following table shows the numbers by percentage of people categorized:

Category	Percentage
1. Apparently good effects of quitting, or bad effects of starting	12%
2. Quitting makes psoriasis worse	15%
3. Smoking (or not) makes no difference	51%
4. People who’d quit smoking a long time prior to psoriasis showing up	7%
5. Other	15%

Clearly, according to these numbers, once you’ve developed psoriasis, whether or not you smoke is rather unlikely to make a difference to the psoriasis symptoms themselves, since only 27% of the authors had any definite effects to report (categories 1 and 2). Of course, a few caveats should be noted: that the people in the above analysis were “self-selected” by the fact that they chose to speak up; that people tend to be fairly bad judges of how their own symptoms are increasing or decreasing; and that many of the newsgroup posts from which I culled the data were old, and the authors’ situations may have changed. Any of the these cautions about the numbers may be true for any of the five categories I used, though, so we can hope the proportions in each category were roughly equal.

Quitting Smoking

I can’t say it enough: regardless of what quitting smoking may (or may not) do to (or for) your skin, quitting smoking will probably do more to boost your overall health than anything else (if you smoke, that is — if you don’t, then don’t start). In other words, stopping smoking may not make your skin any better, but you’ll probably feel a lot better in general (at least, after the withdrawal symptoms go away).

If you’re planning on quitting, however, you might like to know that an Australian study found that use of nicotine patches in people with skin diseases resulted in slightly more “application site reactions” than in people with healthy skin.[22] In other words, if you’ve got psoriasis, and you use “the patch,” you might find that the skin under the patch reacts a little more angrily than other people might experience. Maybe.

Let me close by repeating, again, that whether or not cigarette smoking has any effects on psoriasis, it would probably be better if you quit smoking, or never start smoking. The health effects of smoking cigarettes are well-known and much more likely to do permanent harm than is psoriasis. Again, as Jerry J. said, “Quitting smoking is a far more important step toward future health than anything related to psoriasis.”

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Footnotes

The information provided here is not medical advice. This is not a self-help web site. Seek professional advice before beginning, ending, or changing treatments for any disease or condition. See the legal info page for more information.

This page created on 20020615, and last modified on 20100517.
Copyright © 2002 by Dave W.

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