Itchy Blisters and Pus Bumps on a Food Worker’s Hands for Over a Year: Wet-Work Hand Eczema, What Blood Tests Can Show, Why Patch Testing Matters, and How to Wear Gloves

From our readers: hand blisters for over a year and a blood test next week

A member who works with food described clear blisters on the hands, some turning into pus bumps, with intense itch on waking and scratching until the skin became inflamed.
It has come and gone for more than a year, and a blood test is booked for next week. The question: can the blood test show whether this is an autoimmune disease or something else?
Another member described skin that has become thick, hard and inflamed after long-term itching.

The short answer: blood tests help rule out some conditions and support treatment decisions, but they do not diagnose hand eczema and do not show which kitchen substance the skin reacts to.
Hand eczema is diagnosed from the rash pattern, work history, swabs when there is pus, and patch testing when the rash is chronic.
If you suspect a whole-body allergic rash with severe allergy signs, read
Itchy rash all over, patchy hair loss: allergic rashes and severe allergy signs

1. Why food workers get hand eczema so often

Direct answer: about 9.1% of the general population has hand eczema in a year, but among 1,592 professional kitchen workers in Japan the figure was 32.3%.
(Quaade 2021,
Minami 2018)
Kitchen work combines every risk factor: long periods of wet hands, frequent washing, dish detergent, disinfectants, damp gloves and contact with raw food.

What counts as wet work

The European Society of Contact Dermatitis defines wet work as having wet hands or wearing waterproof gloves for more than 2 hours a day, or washing hands more than 20 times a day.
Hand eczema lasting more than 3 months, or returning at least twice a year, is considered chronic hand eczema.
(Thyssen 2022)

Irritants in the kitchen

Water and the surfactants in dish detergent dissolve the lipids that hold the outer skin cells together. The skin loses water, dries, cracks and lets irritants in more easily.
Vinegar, lime juice, chili, onion, salt and disinfectants then irritate skin that is already cracked. This is irritant contact dermatitis, a common cause of work-related hand eczema.

Allergens in the kitchen

Allergic contact dermatitis happens when T cells learn to recognize a substance and trigger a rash every time it touches the skin again. Kitchen examples include rubber accelerators in gloves,
diallyl disulfide in garlic and onion, and preservatives in cleaning products.
(Kersh 2018,
Moyle 2004)
Another group is protein contact dermatitis from foods such as seafood, wheat flour and raw meat, which usually itches or swells within minutes of contact.
(Barbaud 2015)
It also works the other way: cracked skin lets food proteins in. Among professional kitchen workers, those with hand eczema were about 2.4 times more likely to have a diagnosed food allergy.
(Minami 2018)

Dyshidrotic eczema (vesicular hand eczema)

This rash consists of small clear blisters set deep in the skin along the sides of the fingers and on the palms. It is very itchy and flares in cycles. The word dyshidrosis literally means abnormal sweating,
but the blisters are now known to form from fluid collecting between outer skin cells during inflammation, not from blocked sweat glands.
Common triggers include existing atopic dermatitis, allergic contact dermatitis, stress, hot humid weather and, in some people, nickel or cobalt.
(Lofgren 2006)

Why the itch is worse at night and on waking

At night, cortisol, which dampens inflammation, is at its lowest, the skin loses more water through its outer layer, and nothing distracts from the itch.
Scratching during sleep breaks the skin, creating an itch-scratch cycle that thickens the rash and makes infection more likely.

2. When clear blisters turn into pus: is it always an infection?

Direct answer: not always. Pus bumps on the hands can be a secondary bacterial infection, or sterile pustules that are part of an inflammatory skin disease.
Telling them apart takes a look at the rash plus a swab sent for culture.

Staphylococcus aureus on eczematous skin

A Danish study found S. aureus on the hands of 24 of 50 hand eczema patients, versus 4 of 50 people without eczema,
and those carrying it tended to have more severe eczema.
(Haslund 2009)
Finding bacteria on the skin does not by itself mean an infection that needs antibiotics. Doctors look at increasing pus, yellow crusts, pain and culture results.

From Haslund 2009: 24 of 50 hand eczema patients and 4 of 50 people without eczema.

Sterile pustules on the palms

Palmoplantar pustulosis causes recurring yellow pustules on the palms or soles. These pustules contain no bacteria
and are linked to smoking, so antibiotics do not help.
(Freitas 2020)

Other conditions that look like hand eczema

Fungal infection of the hand is often one-sided with a sharp edge. Scabies itches most at night between the fingers, and others in the household itch too. Psoriasis of the hands has sharp borders and thick scale.
A doctor may scrape scale to look for fungus (KOH) or take a biopsy when the rash does not respond to treatment.
(Thyssen 2022)

Table: types of hand rash and how they are confirmed

Use this to talk with your dermatologist. Real rashes often have more than one cause.

3. Next week’s blood test: what it can and cannot show

Direct answer: no blood test diagnoses hand eczema or shows which substance the skin is allergic to on contact.
The ESCD guideline relies on history, rash pattern, patch testing and tests for infection. Blood tests are used to rule out other conditions when symptoms suggest them, and before starting some oral medicines.
(Thyssen 2022)

CBC, eosinophils and total IgE

High eosinophils or total IgE suggest an allergic tendency, such as atopic dermatitis, asthma or hay fever, but do not say what you are allergic to.
Allergic contact dermatitis is driven by T cells, not IgE, so a normal IgE does not rule it out.
Specific IgE to certain foods is useful when protein contact dermatitis is suspected.
(Barbaud 2015)

ESR and CRP

Both inflammation markers are usually normal when eczema is limited to the skin. Raised values point toward a deeper infection or a whole-body inflammatory disease,
but neither is specific to any one condition. To understand ESR and CRP in autoimmune disease, read
SLE with high inflammation markers and joint pain: reading ESR, CRP, C3/C4

Does a positive ANA mean autoimmune disease?

A US population survey found a positive ANA in about 13.8% of people and about 17.8% of women, most of whom do not have an autoimmune disease.
(Satoh 2012)
A positive ANA does not mean SLE. Diagnosing SLE requires symptoms or organ involvement, such as arthritis, a facial rash, mouth ulcers, or kidney and blood abnormalities.
When symptoms do fit an autoimmune disease and the ANA is positive, doctors go on to test specific antibodies.

Blood tests before oral medicines

Severe hand eczema that does not improve with creams may need oral medicine, so doctors check liver, kidney and blood lipids first.
Women starting alitretinoin need a pregnancy test because the drug causes birth defects, and must use contraception throughout treatment.

Thick, hard skin after long-term itch versus scleroderma

Months of repeated scratching make the skin thicker, with deeper skin lines and darker color, called lichenification. It is a result of scratching and usually softens once the itch is controlled.
Scleroderma is different: finger skin becomes tight and shiny so it cannot be pinched, often after a period of fingers turning white in the cold, and fingertip sores may appear. That situation calls for a rheumatologist.

Table: what each test can show

Results must be interpreted together with symptoms by your treating doctor. Use this to prepare questions before your appointment.

4. Patch testing: finding what your skin reacts to in the kitchen

Direct answer: the ESCD recommends patch testing for everyone with chronic hand eczema, because the rash pattern alone cannot separate allergic from irritant contact dermatitis.
(Thyssen 2022,
Johansen 2015)
Once the allergen is known, staying away from it can improve the rash more than medicine alone.

How a patch test works

Preparing for the test

• Stop steroid creams on the back for at least 1 week and keep the back out of the sun
• Tell your doctor if you take oral steroids or immunosuppressants, or recently had injections of these, because they can suppress results
• Bring samples of your gloves, dish detergent, disinfectant and regular creams so the doctor can add test substances
• Oral antihistamines do not suppress most patch test results and can usually be continued, but check with your doctor

If your hands itch right after touching food, a different test is used

Protein contact dermatitis works through IgE, so it is tested with a prick test using fresh food or specific IgE in the blood. Patch tests are often negative in this group.
(Barbaud 2015)
If your hands itch or swell within minutes of peeling shrimp, cutting fish or kneading dough, tell your doctor.

5. Gloves and hand care during kitchen work

Direct answer: gloves reduce contact with water and chemicals, but gloves themselves trap moisture and can cause allergy. Wearing a cotton layer inside, using gloves only as long as needed, and changing them when damp matter as much as the glove material.

How cotton under gloves helps

In 24 volunteers with experimentally irritated forearm skin, covering with waterproof material slowed skin recovery, while a cotton layer under the waterproof material gave better results than waterproof material alone.
(Heichel 2023)
Change the cotton liner as soon as it gets sweaty or wet. If water gets inside the glove, take it off, dry your hands and put on a fresh pair.

Nitrile gloves can cause allergy too

The main cause of glove allergy is rubber accelerators, such as thiurams and carbamates, which are found in both natural rubber and nitrile gloves.
(Kersh 2018)
Testing of gloves labelled accelerator-free still found accelerators in some products.
(Brans 2023)
Powdered natural rubber latex gloves also carry a risk of immediate latex protein allergy, and vinyl gloves let chemicals through more easily. People who react to gloves should be patch tested and choose gloves based on the results.

Garlic and onion get through gloves

Diallyl disulfide, the main allergen in garlic and onion, penetrates most commercially available glove types.
(Moyle 2004)
Garlic allergy typically affects the fingertips used to hold garlic. A garlic press or chopper helps, and gloves should be changed after cutting garlic or onion.

Washing hands with less skin damage

A comparison study found that alcohol hand rub irritates the skin less than washing with soap and water.
(Loffler 2007)
Kitchen work still requires washing when hands are soiled with food or after handling raw items under food safety rules, so use lukewarm rather than hot water and a small amount of mild soap,
rinse well, pat dry including between the fingers, and apply moisturizer after washing whenever possible.

How much do moisturizers prevent?

A Cochrane review of at-risk workers found hand dermatitis in 13% of those using moisturizers versus 19% of those who did not, with low-quality evidence.
Barrier creams applied before work on their own helped very little.
(Bauer 2018)
Choose a thick, fragrance-free moisturizer such as petrolatum or a ceramide-containing cream, and reapply before bed.

A one-day hand routine for food workers

• Before work: apply a thin layer of moisturizer and let it absorb. Remove rings, which trap water and soap underneath.
• While washing dishes or handling wet items: wear a cotton liner inside and a waterproof glove outside. Keep dishwashing gloves separate from food-handling gloves.
• While preparing food: use food-handling gloves as your workplace requires, and change to a new pair after garlic, onion or seafood, or when a glove tears.
• Every time gloves come off: if hands are damp, rinse with lukewarm water, pat dry and moisturize.
• Before bed: apply prescribed medicine, then a thick moisturizer, and wear cotton gloves to sleep to reduce scratching.

6. Treatment options for chronic hand eczema

Direct answer: treatment starts with stopping contact with the cause, moisturizers and topical steroids. If that is not enough, newer topical medicines, phototherapy or oral medicines follow.
A Cochrane review of 60 trials with 5,469 patients found topical steroids and phototherapy to be the standard treatments, but few trials compared treatments head to head.
(Christoffers 2019)

Trial results for delgocitinib cream

Delgocitinib is a topical JAK inhibitor. In DELTA 1, about 20% of patients on the drug had clear or almost clear hands at 16 weeks versus about 10% on placebo,
and in DELTA 2 about 29% versus about 7%.
(Bissonnette 2024)

Table: comparing treatment options

Generic drug names only. Choice of medicine and duration should be supervised by a dermatologist.

Do you need to stop working?

Most people can keep working by adjusting how they work, such as separating dishwashing from food preparation, wearing cotton liners and giving hands breaks.
During a bad flare or with open sores, a temporary break from wet work helps the skin recover faster and lowers the risk of contaminating food. A medical certificate helps when talking with your employer.

Common beliefs versus the evidence

An ANA test will tell you whether you have an autoimmune disease

About 13.8% of the general population test ANA positive. A positive result without other symptoms does not mean disease, and itchy clear blisters from wet work are not a hallmark of SLE.

A normal IgE means you are not allergic to anything

Allergic contact dermatitis is driven by T cells, not IgE. Finding contact allergens requires patch testing.

Pus always needs antibiotics

Some pustules are sterile, so antibiotics do not help. Doctors decide based on signs of infection and culture results.

Switching to nitrile gloves will stop the allergy

Nitrile contains no latex protein, but it still contains rubber accelerators that cause contact allergy. Even some gloves labelled accelerator-free tested positive.

Steroid creams thin everyone’s skin and should not be used

Hand skin is thicker than most skin. Using the strength and duration your doctor sets lowers the risk. Stopping too early lets the rash return and leads to more scratching and infection.

Frequently Asked Questions (FAQ)

Why do food workers get clear blisters on their hands, and why is the itch worse on waking?

Kitchen work keeps hands wet for long periods, with frequent washing, dish detergent, acidic foods and damp gloves. The lipids holding the outer skin together dissolve, so the skin cracks and becomes inflamed. Some people are also allergic to glove chemicals or garlic. At night cortisol is low and the skin loses more water, so the itch peaks and people scratch in their sleep.

Why do clear blisters turn into pus bumps, and are antibiotics needed?

There are two possibilities. Staphylococcus aureus can infect cracked skin and is found on the hands of about half of hand eczema patients. Or the pustules can be sterile, from an inflammatory skin disease. Antibiotics are used when there are signs of infection, ideally after a swab for culture. Spreading redness or fever means going to hospital today.

Can a blood test show what I am allergic to, or whether I have an autoimmune disease?

No blood test diagnoses hand eczema or shows contact allergens. Total IgE shows an allergic tendency, ESR and CRP show inflammation in the body, and ANA is used for screening when symptoms suggest autoimmune disease. Blood tests are also used before oral medicines. Finding contact allergens requires patch testing.

If my ANA is positive, does that mean I have SLE?

A positive ANA does not mean SLE. About 13.8% of the general population and about 17.8% of women test positive. Diagnosing SLE requires symptoms or organ involvement, such as arthritis, a facial rash, mouth ulcers, or kidney and blood abnormalities. Doctors may test specific antibodies when symptoms fit.

What is a patch test, and how is it different from a blood test?

A patch test places test substances on the back for 2 days, with readings repeated up to about day 7, to find substances that skin T cells remember, such as rubber accelerators, preservatives and metals. Blood tests measure antibodies, a different mechanism. European guidelines recommend patch testing for everyone with chronic hand eczema.

What gloves should food workers wear?

Wear a cotton liner inside and a waterproof glove outside when washing dishes or handling wet items, and change the liner when damp. Use food-handling gloves as your workplace requires and change them after garlic or onion. Nitrile still contains rubber accelerators that can cause allergy, so people whose rash persists should choose gloves based on patch test results.

My hand skin has become thick and hard after long-term itching. Is it scleroderma?

Usually not. Skin scratched repeatedly for a long time becomes thicker, with deeper lines and darker color, and softens once the itch is controlled. Scleroderma makes finger skin tight and shiny so it cannot be pinched, often after fingers turning white in the cold, and fingertip sores may appear. If you have these signs, see a rheumatologist.

How is chronic hand eczema treated, and do I need to stop working?

Treatment starts with stopping contact with the cause, fragrance-free moisturizer and topical steroids. If that is not enough, doctors may use a topical JAK inhibitor, phototherapy or an oral medicine such as alitretinoin, which must not be used in pregnancy. Most people keep working by changing how they work; with open sores, take a temporary break from wet work.

Scientific Mechanism

The skin barrier: the outermost skin layer is arranged like a brick wall. Dead skin cells are the bricks, and ceramides, cholesterol and fatty acids are the mortar.
Water and surfactants dissolve this mortar, so the skin loses water and lets irritants through. Injured skin cells release inflammatory signals, making the skin red, cracked and itchy.
(Thyssen 2022)

Allergic contact dermatitis: small molecules such as rubber accelerators or diallyl disulfide bind to skin proteins. Antigen-presenting cells carry them to lymph nodes, where T cells learn to recognize them.
On re-exposure, memory T cells return to the skin and cause inflammation within 1–3 days. This does not involve IgE, which is why it is tested with patch testing.
(Johansen 2015)

Clear blisters: inflammation drives fluid between outer skin cells until they separate into small cavities. Palm skin is thick, so the blisters sit deep and do not burst easily.
When scratching breaks the skin, S. aureus, usually the same strain the person carries in the nose, multiplies on the inflamed skin and is linked to more severe, longer-lasting eczema.
(Lofgren 2006,
Haslund 2009)

Gloves and trapped moisture: waterproof gloves trap sweat, so the outer skin swells with water and recovers more slowly, as after a long soak. A cotton layer inside absorbs sweat and reduces this effect.
(Heichel 2023)

Compiled and reviewed by Asst. Prof. Dr. Norawit Raatpiboon

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