Dermatographia (skin writing): why a scratch turns into a welt, and what helps

Short answer

Dermatographia, also called dermatographism or "skin writing," is a type of hives in which firmly stroking or scratching the skin raises a red welt along the line within 1–5 minutes; it usually fades in about 30 minutes. If the lines appear but don't itch, it's a harmless skin response; if they itch and keep recurring for more than 6 weeks, it's symptomatic dermatographism, which is treatable.

It often starts suddenly in adulthood, sometimes after an infection, a new medicine or a hard stretch of stress, which is why it feels random and oddly personal. You are not imagining it, and it is not a sign that you are "too sensitive": mast cells in your skin are reacting to friction at a lower threshold than usual. Before you blame yourself, check what your body already recorded.

Note: this article explains a common skin condition and is not medical advice. Hives that come with swelling of the face or throat, trouble breathing, or feeling faint need emergency care, not a better routine.

When is it an emergency?

Dermatographia on its own is not dangerous. The welts are itchy and unsettling, but they stay on the skin and go away by themselves. The problem is that hives of any kind can look similar at first, and a small share of hives are part of a whole-body allergic reaction called anaphylaxis.

Call 911 straight away if hives come with any of these:

• swelling of the lips, tongue, mouth or throat, a hoarse voice or throat tightness

• trouble breathing, wheezing or trouble swallowing

• dizziness, fainting, a racing heart or a sudden sense that something is very wrong

• hives spreading all over the body within minutes to hours of an insect sting, a food or a medicine

If you have been prescribed an epinephrine auto-injector, use it and then call 911. The American College of Allergy, Asthma and Immunology is direct about this: anaphylaxis should be treated immediately with epinephrine, and if you are not sure whether to use it, it is better to use it (ACAAI). If you have no auto-injector, call 911 right away and wait for emergency help.

The pattern that points to plain dermatographia is different: lines that match exactly where something pressed or rubbed, that appear within minutes and are gone within about an hour, with no symptoms anywhere else in the body.

What is dermatographia?

The word means "skin writing," and that is the most accurate description anyone has come up with. Drag a fingernail, a pen cap or the edge of a key across the skin and, a few minutes later, the exact line rises up as a pale or pink raised welt with a red flare around it. It can itch, sting or burn. Then it flattens and the skin looks normal again.

Doctors separate three versions of this response, and the difference between them is mostly about itch.

Physiological red dermographism. Stroke the skin firmly and a red line appears, with no raised welt and no itch. This is ordinary. In the largest international study so far, an online survey of 59,543 adults in 19 countries, it had a point prevalence of about 10% and a lifetime prevalence of about 33% (doi.org).

Simple urticarial dermographism. The line does rise into a welt, but it doesn't itch or bother you. The same study put it at about 1.2% of adults at any given time. It needs no treatment.

Symptomatic dermographism. The welts itch, sometimes intensely, and they appear from everyday friction: a waistband, a bra strap, a bag strap, a towel. This is the condition most people mean when they search for dermatographia. The study estimated a point prevalence of 3.2% and a lifetime prevalence of 5.9% in adults. It is the most common form of chronic inducible urticaria, the group of hives set off by a specific physical trigger (doi.org).

The individual welts are short-lived. The PREVALENCE-D authors describe them as appearing within 1 to 5 minutes and lasting about 30 minutes (doi.org). In a survey of 1,900 people with symptomatic dermographism in Thailand, the median time a welt lasted was 30 minutes, with the middle half of answers between 15 and 60 minutes (doi.org). A welt that stays for more than a day, or leaves a bruise, is not typical and deserves a doctor's look.

What causes dermatographia?

The short version: mast cells. These immune cells sit in the skin and hold histamine and other chemicals ready to release. Friction normally takes a fair amount of force to make them react. In symptomatic dermatographism, the threshold is lower, so a light stroke releases enough histamine to leak fluid into the skin, causing the welt, and to irritate nerve endings, causing the itch.

Why the threshold drops is still not well understood. The authors of one of the most detailed patient surveys wrote that the underlying cause and disease mechanisms "remain obscure" (doi.org). There are clues, though. People with symptomatic dermographism tend to have higher total levels of IgE, the antibody that primes mast cells, and the condition improves with omalizumab, a treatment that removes free IgE. Researchers read both as signs of an IgE-dependent process with some features in common with chronic spontaneous urticaria (doi.org).

It clusters with other allergic conditions. When the same international team compared 3,101 adults with symptomatic dermographism against more than 65,000 without, atopic dermatitis (eczema) was the strongest link, with about 4.2 times the odds, and allergic rhinitis about 2.1 times. People with all three classic allergic conditions, eczema, hay fever and asthma, had about 7.8 times the odds. Female sex, working and older age, thyroid disease and raised cholesterol were also associated (doi.org).

Two things worth saying clearly. Associated does not mean caused: having eczema doesn't mean you will develop dermatographia, and most people with dermatographia have no identifiable cause. And "allergic conditions" here does not mean an allergy to something specific. Dermatographia is not an allergy to your clothes, your towel or your soap. It is a change in how easily your skin's mast cells go off.

Why do I suddenly have dermatographia?

This is the part people find most unsettling. You've had the same skin for decades, and then one week, every scratch leaves a mark.

It really does tend to arrive without warning, and most often in young and working-age adults. In the international prevalence study, the highest rates were in people aged 25 to 60, with a point prevalence of 3.8% in that group (doi.org). In a Turkish clinic series of 40 people with symptomatic dermographism, patients were on average 30 years old (doi.org). It can start earlier: in the large Thai survey, the median age of the first episode was 16 (doi.org). But plenty of people first notice it in their twenties, thirties or later, with no skin history at all.

It can follow stress, an infection or a medicine. That same Turkish study looked for what happened around the time symptoms began. In 30% of patients, psychological stress appeared to play the initial triggering role. In 7.5%, symptoms began after a drug-induced urticarial rash. One case appeared alongside scabies, a skin infestation, and one followed a streptococcal infection with kidney inflammation. For most, no specific event was found (doi.org).

That study was small, and "a close temporal relationship" is not the same as proof of cause. But it matches what many people describe: the welts showed up after a bad flu, a course of antibiotics, a move, a breakup or a punishing few months at work. If that is your story, it is a recognised one.

It is more common in women. In the international survey, point and lifetime prevalence were higher in women than in men in every age group (doi.org), and 73% of the participants with symptomatic dermographism were female (doi.org).

What triggers dermatographia flares?

The underlying trigger is always friction or pressure across the skin. What changes from day to day is how much friction you meet and how reactive your skin is that day.

In the Thai survey, people with symptomatic dermographism most often named these as making it worse (doi.org):

• stroking or scratching the skin (57%)

• tight clothes (57%)

• rubbing against objects, such as the edge of a table (33%)

• stress (19%)

• drying off with a towel after a shower (8.5%)

Among people who noticed a weather pattern, most said hot weather made it worse, and changes in temperature were one of the factors most strongly linked with having the symptomatic form rather than the harmless one.

Many people notice it is worse in the evening. In a German survey of 91 patients, 81% said symptoms were worse in the evening, and 44% said stress set off acute episodes (doi.org). Why evenings are worse has not been established. The day's accumulated friction, getting undressed, a hot shower and the fact that itch is harder to ignore when you stop moving are all plausible contributors, but no study has pinned it down.

What about stress? Here the evidence is less tidy than it sounds. People with dermatographia regularly report that stress makes it worse, and a stressful period often precedes the first episode. But one experiment cited by the Thai researchers found that acute psychological stress in the lab did not change the size of dermographic welts, and those authors concluded that the effect of stress on flares "remains uncertain" (doi.org).

One way these fit together: stress may not make the welt bigger, but it can make you itchier, sleep worse and scratch more without noticing. And in dermatographia, scratching is not just a response to the itch; it is also the trigger. Scratch an itchy patch and you write fresh welts, which itch, which you scratch. That itch–scratch cycle is why a mild flare can turn into a miserable evening, and why the most useful thing you can do is often to interrupt the scratching rather than to find a hidden cause. For more on how stress and hives interact, see our guide to stress hives.

Dermatographia, chronic hives, MCAS: how are they different?

Dermatographia often sits alongside other kinds of hives, and it gets mixed up with conditions that are quite different.

Chronic spontaneous urticaria (CSU). These are hives that appear on their own, without friction, on most days for 6 weeks or longer. The two conditions overlap a lot. In the Thai survey, 21.5% of people with dermatographism also had spontaneous welts (doi.org). In an international registry of 4,332 adults with chronic urticaria, 21% had CSU together with at least one inducible type of hives (doi.org). If you get welts that you did not write, and they last for hours rather than half an hour, read our explainer on chronic spontaneous urticaria; treatment follows the same ladder, but it helps your doctor to know both are present.

Other inducible hives. Tiny, pinpoint welts that appear when you get hot or sweaty are more likely cholinergic urticaria. Welts after cold exposure are cold urticaria. Deep, painful swelling that appears hours after sustained pressure, from a bag strap or sitting on a hard chair, is delayed pressure urticaria, a separate condition. You can have more than one of these at once.

MCAS (mast cell activation syndrome). Hives involve mast cells, so it is easy to leap to MCAS. But hives alone are not MCAS. That diagnosis involves repeated episodes affecting several body systems at once, such as skin plus gut, breathing or blood pressure, together with evidence of a rise in mast cell chemicals during episodes and a response to mast cell treatment. Our article on mast cell activation syndrome explains the criteria.

Histamine intolerance. This refers to symptoms after histamine-rich foods and drinks, mostly gut symptoms, headache and flushing, thought to come from reduced breakdown of histamine in the gut. It is not triggered by friction, and a low-histamine diet is not a treatment for dermatographia. See what histamine intolerance is if food reactions are your main concern.

How is dermatographia diagnosed?

Usually in a few minutes, in the doctor's office. The test is the condition: the clinician firmly strokes the skin of your forearm or upper back with a smooth, blunt object, such as a closed ballpoint pen or a wooden spatula, and watches for an itchy, raised line.

Specialist clinics sometimes use a device that applies a standard amount of pressure. One is a spring-loaded dermographic tester, which strokes the skin at a pressure of 36 g/mm² (doi.org). Another is the FricTest, a small plastic comb with pins of different lengths. In a validation study of 30 patients and 30 healthy volunteers, a welt of 3 mm or wider at the strongest pin identified every patient and none of the volunteers (doi.org). Because the pins apply different forces, the test also shows your threshold, which is useful later to see whether treatment is working.

Extensive blood tests and allergy panels are usually not needed. The 2026 international urticaria guideline recommends provocation testing to diagnose inducible urticaria. For symptomatic dermographism, the routine workup is the stroke test with a threshold test; a blood count or inflammation markers are added only when the history suggests them. The guideline also recommends tracking control over time with threshold tests and a short questionnaire, the Urticaria Control Test (doi.org). If your allergy tests came back clean, that is expected. It does not mean nothing is wrong; it means dermatographia is not an allergy.

Many people wait a long time for a name. In the chronic urticaria registry, people with inducible hives only, the group dermatographism belongs to, waited longest for a diagnosis: a median of 4 months, against 1 month for spontaneous hives alone. Across all patients, 24% waited at least a year (doi.org).

Does dermatographia go away?

Often, but it can take years, and the data on how many people recover is thin.

In the German survey, the average duration of disease was 6¼ years. For most, it was continuous, but about 25% had long symptom-free phases (doi.org). In the Turkish clinic series, duration ranged from 10 days to 10 years, with an average of about 21 months (doi.org). In the Thai survey, about half of the people who had ever had dermographism still had it when they answered the questionnaire (doi.org).

Specialist clinics see the most persistent cases, so their averages probably overstate how long a typical case lasts. What can be said fairly: dermatographia is often a matter of years rather than weeks, it tends to wax and wane, and there is no good way yet to predict who will clear quickly. That is exactly why controlling symptoms matters more than waiting it out.

It also has a real cost. In the German survey, 44% said their quality of life was significantly impaired, and 7% said a normal life was not possible (doi.org). Nearly 30% of people with symptomatic dermographism in the Thai survey reported moderate to severe effects on daily activities and sleep (doi.org). If it is wearing you down, that is a reason to treat it, not a sign of overreacting.

How to get rid of dermatographia: what treatment can do

There is no quick fix that removes dermatographia for good, because it often lasts years. What treatment can do is keep symptoms under control while the condition runs its course. There are two parts: reducing friction, and medicine for when that isn't enough.

Everyday measures. None of these has been tested in a trial, but they follow directly from how dermatographia works, and they cost nothing:

• choose loose, soft clothing and wider straps, and swap tight waistbands for softer ones

• pat skin dry after showering rather than rubbing with a towel

• use lukewarm rather than hot water, and a cool compress on an itchy patch

• keep nails short, and press or pinch an itchy spot instead of scratching it

• carry a bag across the body with a padded strap, or switch shoulders

Medicine follows a ladder. The 2026 international urticaria guideline sets out one step-by-step algorithm for chronic urticaria, and its first steps apply to inducible types such as dermatographism as well as to chronic spontaneous urticaria (doi.org).

The first step is a second-generation, non-sedating H1 antihistamine, such as cetirizine, loratadine or fexofenadine, which the guideline recommends as first-line treatment for all types of urticaria. For inducible hives, it suggests deciding with your doctor whether to take it every day or ahead of predictable triggers; the guideline favours continuous use when symptoms are very active or poorly controlled. Older, sedating antihistamines are not recommended as first-line treatment because of drowsiness and other side effects.

If standard doses don't control symptoms, a doctor may raise the dose above the usual label amount. That step is for a clinician to decide, not to try on your own.

If symptoms remain uncontrolled, the guideline's next step is adding omalizumab, an injected biologic that targets IgE. It is licensed for chronic spontaneous urticaria and has also been reported to help symptomatic dermographism. Ciclosporin, an immune-suppressing medicine, is kept for severe cases that don't respond to licensed treatments, under specialist monitoring.

Newer targeted options now exist for chronic spontaneous urticaria. Remibrutinib, a tablet that blocks Bruton's tyrosine kinase, an enzyme involved in switching mast cells on, was approved by the FDA in September 2025 for adults whose hives stay active despite antihistamines, and the 2026 guideline also includes dupilumab, an injected biologic (doi.org). Both are recommended for spontaneous hives, not established for dermatographia on its own, so if you have both conditions, ask a specialist whether they apply to you.

What the evidence says for dermatographia specifically. A 2020 systematic review found 23 studies, including 15 randomised trials, covering 430 adults (doi.org). Second-generation H1 antihistamines were effective and well tolerated in every study that tested them. An H2 antihistamine on its own did not work, but adding one to an H1 antihistamine increased the effect. Symptomatic dermographism improved with omalizumab. The reviewers also pointed out that there are no studies of higher-dose antihistamines in dermatographia specifically, so that step is borrowed from the evidence in chronic spontaneous urticaria.

In the German survey, almost everyone was taking an H1 antihistamine: 49% reported marked improvement and 23% became symptom-free (doi.org). So antihistamines help most people, but a sizeable group needs the next step, and that group deserves a specialist rather than a shrug.

What doesn't help. Allergy elimination diets are not a treatment for dermatographia unless a specific food reaction has been found. Neither is avoiding a long list of "histamine foods," replacing all your laundry products or testing for dozens of allergens. None of these addresses a lowered friction threshold in the skin.

Living with dermatographia: the questions people ask next

Once you have a name for it, the next questions are practical ones: whether it's serious, whether you can train, shave or get a tattoo, and whether what you eat or your cycle makes a difference. Each answer below stands on its own.

How common is dermatographia, and is it contagious?

Dermatographia is not rare. In the PREVALENCE-D survey of 59,543 adults in 19 countries, itchy symptomatic dermatographia affected about 3.2% of adults at the time they answered and 5.9% at some point in their lives, and a harmless red line after firm stroking showed up in about 10% (doi.org). That makes symptomatic dermatographia the most common type of hives set off by a physical trigger. It is not contagious either. The welts come from mast cells in your own skin reacting to friction, not from a germ, so nobody can catch dermatographia by touching you, sharing a towel or sleeping in the same bed.

What infections cause dermatographia?

No infection has been proven to cause dermatographia, but a few have been linked to when it started. In a Turkish clinic series of 40 people with symptomatic dermatographia, one case appeared alongside scabies and one followed a streptococcal infection with kidney inflammation, so infection was an uncommon link there (doi.org). Doctors have also described a case of dermatographia during COVID-19 that faded over the following weeks (doi.org). For chronic hives in general, the 2026 guideline lists infections such as H. pylori among possible causes or aggravating factors, notes that the link is often unclear for an individual patient, and advises against broad screening programmes (doi.org). If your dermatographia began after an illness, tell your doctor, who can decide whether any test is worth doing.

Could dermatographia be a sign of something serious, like cancer?

For most people, no. In the Turkish clinic series of 40 people with symptomatic dermatographia, researchers looked specifically for autoimmune, malignant and other systemic diseases and found none (doi.org). In the international PREVALENCE-D survey, a cancer diagnosis was reported by 1.2% of the 3,101 adults with symptomatic dermatographia and 1.3% of those without it, a difference that was not statistically significant (doi.org). The 2026 urticaria guideline says an underlying cancer has been reported only very rarely in chronic spontaneous hives and advises against intensive screening (doi.org). Dermatographia that behaves differently deserves a doctor's look: welts lasting more than 24 hours, bruising, fever, or joint or bone pain.

Can I exercise with dermatographia?

Yes, and exercise may even help. In one study of people with symptomatic dermatographia, a short bout of exercise reduced the skin's reaction to the FricTest in 83% of 58 patients (doi.org). A follow-up asked 34 patients to do at least 30 minutes of moderate exercise a day for a month; afterwards, their Urticaria Control Test scores and quality of life had improved (doi.org). Both studies were small and had no comparison group. With dermatographia, the part to plan for is friction: wide, padded straps, a well-fitted sports bra, smooth fabric where seams rub, and a lukewarm shower afterwards. Heat is worth watching too: in PREVALENCE-D, about 6 in 10 people with symptomatic dermatographia said temperature affected their skin, and hot weather was the most common aggravating factor, named by 48.4% of them (doi.org).

Can I shave, wax or get a tattoo with dermatographia?

There is no evidence-based rule either way, but expect some welts: shaving, waxing and tattooing all drag or press across the skin, and in dermatographia friction is the trigger. We found very little research on tattoos in people with dermatographia. A practical approach: tell your tattoo artist beforehand, so raised lines aren't mistaken for a reaction to the ink; ask your dermatologist whether to take your usual antihistamine before the session; and consider starting with a smaller piece. For hair removal, a sharp razor with plenty of shaving gel drags less than a dull or dry blade. In a Thai survey, dermatographia welts typically lasted about 30 minutes (doi.org); redness that lasts for days needs a doctor's look. If pain is your main worry, see our tattoo pain chart.

Do food, alcohol or your period make dermatographia worse?

Food may matter, but not in the way elimination diets promise. In a study of 64 people with symptomatic dermatographia, 66% reacted more strongly to the FricTest after an ordinary carbohydrate-rich meal, and 13% reacted only after eating. Exercise prevented that post-meal worsening in about half of cases, more often when done after the meal (doi.org). That points to eating itself, not to one "bad" food. We found no study on alcohol in dermatographia specifically. For periods, 7.9% of people with symptomatic dermatographia in the Thai survey said menstruation made it worse, and the authors noted that a link with hormonal changes has not been described (doi.org). A practical approach is to note meals, drinks and cycle days next to flares and look for your own pattern.

Is it safe to take antihistamines for dermatographia for months, or in pregnancy?

The 2026 international guideline supports daily use of modern non-sedating antihistamines partly because of their safety record: safety data cover several years of continuous use and use in pregnancy (doi.org). The older, sedating antihistamines are different; the guideline warns that they cause drowsiness, interact with alcohol and other medicines, can disturb REM sleep and impair tasks such as driving. For pregnancy and breastfeeding, its position is to avoid systemic medicines where possible, especially in the first trimester, while recognising that pregnant women have the right to effective treatment, so decisions are made after weighing benefits and risks. Which medicine to take, for how long, and whether to pause it during pregnancy is a decision for you and your doctor.

How do I sleep with dermatographia, and stop dreading the next flare?

Nights are often the hardest part: in the Thai survey, about a quarter of people with symptomatic dermatographia said it moderately or severely affected their sleep (doi.org). A practical bedtime routine is a lukewarm shower, patting dry, loose sleepwear, a cool bedroom, short nails and a cool compress within reach. An old sedating antihistamine is not a guideline-backed sleep aid, because those medicines can disturb sleep quality. The worry is real too. In PREVALENCE-D, 13.8% of people with symptomatic dermatographia reported stress and 11.1% anxiety because of it, and distress rose with itch severity (doi.org). Feeling self-conscious about marks on your skin is not vanity. If it is wearing you down, tell your doctor: better itch control is part of looking after your mood.

How to bring this up with your doctor

Dermatographia is easy to underplay in a short appointment, partly because the skin often looks completely normal by the time you are seen. A little preparation makes it much harder to dismiss.

What to track for two weeks:

• photos of the welts with the time, and a second photo 30–60 minutes later to show how quickly they fade

• where they appear and what rubbed there: waistband, straps, towel, scratching

• how bad the itch was, on a 0–10 scale, and whether it woke you or kept you from sleep

• any welts that appeared without friction, and how long those lasted

• new medicines, recent infections, and stressful periods around when it started

What to say: "When anything rubs my skin, I get raised, itchy lines within minutes that fade in about half an hour. It started around [month], it's happening [how often], and it's affecting my sleep and work." Then offer to demonstrate: a firm stroke on your forearm in the office shows the doctor the diagnosis in real time.

What to ask:

• Is this symptomatic dermatographism, chronic spontaneous urticaria, or both?

• Could any of my medicines or a recent infection be involved?

• Which antihistamine should I take, and should I take it every day or only before known triggers?

• If it isn't controlled, when would you change the dose or refer me to an allergist or dermatologist?

• Do I need any tests, or is the stroke test enough?

Mention straight away if welts last longer than 24 hours, leave bruises, come with fever or joint pain, or if you ever get swelling of the lips, tongue or eyelids. Those point away from simple dermatographia and need a different workup.

"I'm just too sensitive": what your body already recorded

The feeling. Dermatographia has a way of turning into a judgment about yourself. The welts appear from things other people don't even notice, a seatbelt, a sweater, your own fingernails, and it is easy to conclude that your body is overreacting, that you are fragile or that this is all nerves. Some people are told exactly that.

The visible cause. Look at when your flares are worst and there is usually something ordinary behind it. A week of short nights, a heavy stretch at work, the tail end of a cold, a new medicine, a hot spell, a new pair of jeans. The itch is worse when you're run down, you scratch more when you're tired or stressed, and each scratch writes a new welt. None of that is a character flaw. It is a lowered friction threshold meeting a demanding week.

Permission, and one lever. You don't need to fix everything at once, and you don't need to find a single hidden cause. Pick one lever for the next two weeks: stop the scratching by pressing, pinching or cooling instead, and keep your nails short. Keep taking whatever your doctor has recommended. Then watch the trend: are there fewer evenings where one scratch turns into twenty? A small, visible improvement over one to two weeks is more useful than any amount of self-blame.

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How Welltory helps — and what it cannot do

The limits first. Welltory is a general wellness product, not a medical device. It does not detect, diagnose, predict or treat hives, and it cannot see your skin.

What it can do is help with the part of dermatographia that memory handles badly: what happened around a flare, and what your body was carrying in the days before. Here is a routine that fits this condition.

Track the flare, not just the itch. When Welltory flags a stress stretch and asks "What happened?", you can tap a suggested tag, type a few words or just talk. Use that moment to log the flare itself, such as "hives flare" or "itchy evening", and the friction you suspect: "tight waistband", "backpack", "new jeans", "rough towel", "long drive with a seatbelt". Two or three words are enough. If you use Journal, the Premium feature for taking several measurements a day, a quick reading on a bad evening adds one more data point.

Look at the days before. Friction writes the welts, but how itchy you feel and how much you scratch can shift with the rest of your life. For each tagged flare, look at sleep, stress minutes, Battery, resting heart rate and HRV in the one to three days before. Were the worst evenings preceded by short nights, a long run of stress minutes or a Battery that never recharged?

Let My Patterns do the sorting. After roughly two to three weeks of tagging (at least 7 tagged occurrences in the current month, with some history from the month before), My Patterns shows which tagged situations tend to come before stressful stretches, which tags "don't happen often but hit your body hard", trends by day of week, heart-rate data, and a complete list of every time a tag happened. That list can show, for example, whether your flares bunch up on particular weekdays.

Bring a personal log to your doctor. Dermatographia welts are usually gone by the time you are seen, so the list of tagged flares and your notes becomes a ready timeline for the appointment. Add phone photos of the welts, ideally with a second photo 30–60 minutes later, and your Urticaria Control Test score if your doctor uses it (or the UAS7, if you also have chronic spontaneous urticaria). From the Welltory web app, you can export your data as a CSV file (Dashboard → choose a chart → Export) to share with a specialist.

Two caveats. These signals are not specific to skin: alcohol, a warm bedroom, illness and a hard workout move them too, so read patterns across weeks rather than single days. And if checking the data starts to feel like another way to find fault with yourself, check less. If stress seems to be part of your picture, our guide to stress hives goes further.

Whatever the patterns show, they are associations to discuss with your doctor, not proof of a trigger.

How we made it

Made with AI tools, then edited and fact-checked by the Welltory team. See our Editorial & AI policy.

Data analysis by Jane Smorodnikova, co-founder of Welltory and the person who built the methodology behind how we read physiological data.

Written by Tatsiana Yashyna.

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