Hand Dermatitis Tracks How Often You Wash, Not How Cold It Is. Nearly All the Evidence Comes From People at Work.

The knuckles go first. Then the web between thumb and index finger, then a split beside a nail that reopens every time you make a fist. It arrives in October and everybody blames October.

The research does not really support that. Almost all of the work on preventing irritant hand dermatitis was done on people at work — nurses, factory workers, hairdressers, metalworkers — and the exposure the researchers were tracking was not the weather. It was how many times a shift somebody washed.

Cold air is not helping. It is just not the variable anyone measured.

Why the studies are all about work

Look for trials on preventing hand dermatitis and you land in occupational medicine. Arbogast and colleagues tested a hand-care regimen with moisturiser in manufacturing facilities where workers were already prone to irritant dermatitis, published in 2004. A double-blind randomised study from 2010 compared different moisturisers against dermatitis induced by a hand-washing protocol built to simulate healthcare use. Cochrane pulled the field together in a review of interventions for preventing occupational irritant hand dermatitis in 2018.

Nobody runs these in the general population, because the general population does not wash often enough to produce an endpoint inside a study window. You need people doing it twenty times a shift to see something in twelve weeks.

Which tells you what the driver is. If frequency is the only reliable way to produce the condition on purpose, frequency is what is producing it accidentally.

Ten days from one wash

Here is the piece we could read in full, and it is the one that changed how we think about this.

Löffler and Happle patch-tested detergents in Contact Dermatitis in 2003, at concentrations from 0.125% to 2.0%, with exposures of six to twenty-four hours. Then they measured water loss and blood flow at 24 hours, at day 7, and at day 10. Sodium lauryl sulfate was still producing detectable effects at day 10 across the whole concentration range.

Ten days. From one exposure.

A patch test is harsher than a hand wash — occluded, held against skin for hours, no rinse. The point is not the magnitude. The point is the timescale. Skin recovery from surfactant exposure is measured in days, and the gap between your washes is measured in hours.

That is the whole model. Not "this soap is bad". Just: the damage is slower to heal than the interval between insults, so it accumulates, and by week three of a cold snap with more hand washing than usual, it shows.

What the trials actually intervened with

The tested intervention is almost always a moisturiser used as part of a regimen. Not a gentler soap, not gloves alone, not a barrier cream on its own. A cream, applied on a schedule, usually after washing.

The schedule is the part people drop. A moisturiser sitting beside the sink that gets used twice a day is not what any of these studies tested. They tested application tied to the exposure, which for a nurse means most of the twenty times.

None of this requires an expensive product. The occupational trials were run with ordinary workplace hand creams, because the question was whether a regimen works, not whether a formula is special.

Six fragrance allergens on the site where contact dermatitis is most common

Our own hand and body lotion has fifty-two ingredients. Eleven of them carry a flag from us, and six of those eleven are named fragrance allergens: benzyl salicylate, linalool, hydroxycitronellal, limonene, coumarin and benzyl benzoate. There is a general fragrance line above them.

Hands are the single most common site for contact dermatitis. They are also the site with the most repeated exposure and the most compromised barrier by the time somebody goes looking for a cream. Putting a full declared allergen set on that site is a decision we would argue with.

It smells extremely good, and that is not nothing — people use a cream they like the smell of, and adherence is the whole ballgame in a regimen study. We are not pretending the trade-off does not exist. We are saying that if your hands are already cracked, this is the wrong bottle, and we sell better options for that specific situation, including a fragrance-free barrier cream that carries no allergen declarations at all.

One smaller thing while we are here: we grade this product's dimethicone mid, and we grade the same dimethicone low in six other products. That is our inconsistency, not the formulator's.

What our screening found

The practical takeaway

Count your washes for a day. Not to change the number — most of those washes need to happen — but because the number is the thing driving this, and knowing it tells you how often the cream has to go on.

Apply after washing, on hands that are still slightly damp, rather than on a schedule of your own. The trials tied application to exposure and that is the part worth copying.

Water temperature is the free win. Hot water strips lipids faster than warm water and nothing in a hand wash requires heat to work.

Pick fragrance-free for hands specifically, even if you happily use scented products everywhere else. It is the highest-exposure, highest-damage site you have, and it is the one place where the trade-off tips. We have counted which of our products declare fragrance and which quietly do not, which is a useful place to start. The ingredients we flag most and our full method are on the awards page.