Chilblains are red, often swollen, often painful or itchy places on the hands, feet, fingers, toes, or other places like ears and nose. Since I have them almost only on the hands and fingers, I will limit myself to discussing that form from my own experience. The chilblains result from a blood circulation problem in the hands; when the hands get cold (and later warm again), something happens to the capillaries such that the blood does not fit properly through them, causing a kind of congestion which shows up as redness and swelling when the blood leaks from the blood vessels into the tissues. The mechanism of chilblain formation is explained more precisely elsewhere, and different sources give somewhat different explanations, so I will not attempt to go into those details; actually it seems one is not fully certain of the exact causal mechanism. When it gets bad, the fingers may also get stiff and there may be some loss of strength in the hands (because it hurts to exert force). The skin over the chilblains is vulnerable and bursts easily.
Chilblains seem to occur more often in persons who have lost weight or have a low body mass, and more often in females than in males. I do not know exactly why these differences in occurrence frequency exist, but I could imagine that it has to do with having difficulty to keep the extremities warm. While considered a harmless condition, there are a number of serious diseases that resemble or go with chilblains, so that it may be wise to consult a doctor for examination in persistent cases of chilblains.
Hereafter I will discuss a number of possible measures to reduce or prevent chilblains, based on my own experience and insight.
To my experience it is necessary to wear gloves outside when it gets colder than about 10 °C. The exact temperature threshold also depends on the wind; with some wind it may be 12 degrees, without wind 8 degrees. When it gets around or below 0 °C, thicker gloves are needed, like ski gloves. It is needed to anticipate the fact that in open fields, as well as inside a forest, it is colder than in a build-up area. While gloves do not solve the problem completely, they certainly help, and without gloves the chilblains would quickly become much worse and the fingers end up as bloody stumps.
Do note that the gloves are not worn because one could otherwise not bear the cold on one's hands! They are merely worn to prevent or reduce chilblains. One can stand much lower temperatures than mentioned above without gloves, and that is why it takes discipline to consistently wear gloves; one has to wear them without feeling the need to wear them.
When, for some reason, one has to work in a room where the temperature is such that one's hands feel cold, a solution is to wear gloves with a rubber profile on the inside of the hands so that activities like typing and grabbing small things are possible. Worker's gloves for fine work, for instance, are suitable. One has to learn by experience to feel when the hands are so cold that the chilblains will get worse, and at those times one has to take measures like this.
Once one has chilblains, it is good to keep the hands dry as much as possible and avoid extreme temperature changes. With tasks involving (hot) water like doing the dishes and cleaning, rubber household gloves are very effective regarding that.
During cold periods, which tend to coincide with chilblain suffering, the skin of the hands tends to be dry. By applying some cream regularly, especially after washing the hands, the skin can be moisturized and will less easily burst and bleed. Even though the cream has little or no effect on the chilblains themselves, it is wise to do this for that reason. A basic cream like Nivea suffices. Note that dryness of the skin is a condition separate from chilblains, not to be confused with them. Dry skin occurs when air humidity is low, chilblains are said to be more related to high humidity combined with cold.
Since chilblains appear to be related to (or worsened by) weight loss and/or having a low body mass, gaining a few kilograms may reduce one's disposition for the condition. If one has a relatively low body mass index, this could be worth trying. Simply eat more at each meal, or insert an extra meal each day. If one is at risk of becoming overweight and/or diabetic, this may not be the way to go.
On the upper body, underwear with long sleeves helps to keep the arms and hands warmer, or less cold.
Blood flow to and from the arms may be affected by tension in the shoulders. Tense shoulders are typically held too high. Exercises for the neck and shoulders may, at least temporarily, send more blood into the arms and hands. One can find such exercises described in many places, for instance in Exercises for knees, back, and neck under Exercises for the neck and shoulder area... After five to ten minutes of rotating the shoulders and swinging the arms, the hands should become warm (for some time). The neck exercises are relevant because too tight neck muscles pull the shoulders upward.
In this respect it is interesting to mention that, in the early 1990s, I had Mensendieck therapy (posture therapy) for about a year. The therapist noted that I had cold hands, and said this was because the tension in my neck and shoulders restricted the blood vessels so that not enough blood got into the arms. Although this seems plausible, I have never found out if it is the full explanation. Are the hands cold because not enough blood flows into the arms, or are they (also) cold because the blood vessels in the hands themselves are not good? This question remains unanswered for the moment.
Incidentally, the often heard advice to move (open and close) one's hands and fingers when it is cold to thus keep the circulation going has no effect whatsoever to my experience, probably because the cause of bad circulation in the hands lies not (or not only) in the hands themselves but (also) higher up, at least in my case.
I suspect that an increase of muscle mass in the shoulders and arms would help to keep the arms and hands warmer, and thus reduce the problem of chilblains. Unfortunately, I can not experience this myself because my muscles refuse to get bigger, no matter how I train. It is a matter of disposition.
If one suffers badly from chilblains, doctors may be willing to prescribe pills to dilate the peripheral blood vessels. I have not tried this myself because I fear the possible side effects and think my chilblains are not bad enough for medication. Interestingly, serotonin reuptake antagonists (a group of antidepressants) like paroxetine are also used for this purpose; because of the side effects I would not want to take them myself for treatment of chilblains. Remarkable is that I have used paroxetine for five years for another reason, and when I stopped taking it began to get chilblains for the first time in my life.
Several herbal substances are said to be effective against chilblains, in particular because of their effect on the blood circulation. Examples are Ginkgo biloba and Melilotus officinalis (yellow sweet clover); it concerns extracts of these plants, not the plants themselves. In case one wants to experiment with these herbs, I would advise to study their possible side effects and interaction with other medication first. I have so far tried a herbal tea with both herbs just mentioned, but noticed no effect. Perhaps tea is not the right method of administration?
Raising the temperature in one's house reduces or prevents the problem of having cold hands, and should be beneficial with regard to chilblains. Because of the additional energy consumption and exhaust of gasses, this should perhaps not be the first thing to try.
Some sources recommend alternating hot and cold baths (of the hands or feet), especially before a cold period, to prevent chilblains. This is somewhat paradoxical, considering the aforementioned advice to avoid extreme temperature changes, although it could be understood as a form of resistance training for the capillaries. Again, different sources give diametrically different descriptions of the method; the one source will say, "3 minutes in hot water and then 30 seconds in cold water", the next, "3 minutes in cold water, then 30 seconds in hot water". The one will say, "always end with hot water", the other, "always end with cold water". It is entirely speculative. I have not tried it.
There is a highly interesting theory by Konstantin Buteyko to the extent that many health problems are caused by what he calls "chronic hyperventilation" and the reduced level of carbon dioxide in the blood that results therefrom. His method and theory can not be discussed in full here, but with regard to chilblains it is relevant that a low CO2 level causes involuntary muscles (controlled by the autonomous nervous system) to contract. Around the capillaries lie such muscles too, and their contracting under hyperventilation would restrict blood flow and thus cause cold hands and chilblains, according to this theory. Buteyko's breathing retraining method would then be the solution. I have not tried it, but if a course were available near me I would want to participate as I find this very plausible.
While no fully proven treatment of chilblains appears to exist, simple measures like gloves, cream, and warm loose clothing are effective when kept up diligently. If the problem persists, it may be wise to see a doctor for further treatment and/or to test for a number of more serious conditions that might be behind it.
It is problematic to pinpoint a single cause of chilblains. Is it only a malfunction of the capillaries? Or is it (also) the more general phenomenon of not being able to keep the extremities warm, which one sees in underweight or skinny persons, anorexics, long-distance runners and the like? In other words, does the cause lie locally where the chilblains occur, or is it a global problem involving the whole body? I wonder.