17725 Sweet Syndrome

Overview

Sweet syndrome is a rare skin condition that causes fever, feeling unwell, and sudden, painful, reddish bumps or plaques on the skin. It is not an infection and not contagious. It happens when the immune system overreacts and a type of white blood cell (called a neutrophil) builds up in the skin, causing inflammation and redness.

No, Sweet syndrome is rare. It affects only a small number of people each year, so most doctors see few cases in their career.

It can affect anyone, but most often appears in adults aged 30 to 60 and is more common in women. Children can get it too, but it is less common. People with certain blood disorders or inflammatory bowel disease have a higher chance of developing it.

Symptoms

Common symptoms

• Sudden painful, red or purplish lumps or plaques on the skin
• Fever, often starting before the rash appears
• Tenderness or pain in the affected skin
• Fatigue, headache, or joint pain
• Skin may look like it has blisters or open sores

Symptoms in children

• The rash often appears on the face and cheeks
• Fever is common
• The rash may look like a bruise or have blister-like bumps
• It often follows an upper respiratory infection

Symptoms in older adults

• The rash may be larger and more widespread
• There is a higher chance it is linked to a medication or an underlying blood cancer
• Mouth ulcers or eye redness may occur
• The illness can be more severe

Causes

Main causes

• The exact cause is unknown, but Sweet syndrome is believed to be a hypersensitivity reaction where the immune system overreacts to a trigger.
• Infections (especially of the upper respiratory tract) can trigger it.
• Certain medications, such as some antibiotics or anti-inflammatory drugs, may trigger it, though this is uncommon.
• Pregnancy can sometimes trigger it.
• Underlying conditions like inflammatory bowel disease or blood cancers (such as leukemia) are linked to Sweet syndrome.

Risk factors

• Being female
• Being between 30 and 60 years old
• Having recently had a cold, flu, or other respiratory infection
• Starting a new medication
• Being pregnant
• Having inflammatory bowel disease (Crohn's disease or ulcerative colitis)
• Having a history of a blood cancer

When to see a doctor

See a doctor urgently if:

• You have a sudden, painful skin rash with a fever or feel very unwell.
• You have a known blood disorder or weak immune system and develop a rash.
• You develop blisters, open sores, or signs of infection.

Book a routine appointment if:

• You have a rash that is spreading or not going away.
• You are concerned about the appearance of your skin.
• You want to find out if the rash could be linked to a medication you are taking.

Diagnosis

A doctor, usually a dermatologist, will examine your skin and ask about your symptoms, medicines, and recent infections. To confirm Sweet syndrome, they will often do a skin biopsy – a small procedure where a tiny piece of skin is removed and looked at under a microscope. Blood tests are also usually done to check for inflammation and to look for other causes.

Tests that may be done

• Skin biopsy (taking a small sample of skin for testing)
• Blood tests to check white blood cell count and signs of inflammation
• Blood tests to look for underlying conditions, such as blood cancers
• Throat swab or other infection tests if an infection is suspected
• Chest X-ray or other imaging if a lung problem is suspected
• Stool tests if inflammatory bowel disease is suspected

What to expect at your appointment

The skin biopsy is done with a local anaesthetic, so you will not feel pain. It usually takes less than 30 minutes. Results may take about a week. Your doctor may discuss starting treatment while waiting for results, especially if your symptoms are severe. You may also be referred to a specialist, such as a haematologist (blood specialist), to check for underlying conditions.

Treatment

Treatment focuses on reducing inflammation and clearing the rash. Most people need medication, often steroid medicines, which are strong anti-inflammatory drugs. Your doctor will also look for and treat any underlying cause, such as an infection or a reaction to a medicine. The rash usually improves within days to weeks with treatment, but you may need to keep taking medicine for a while to prevent it from returning.

Self-care at home

• Rest while your body is fighting the inflammation.
• Wear loose, soft clothing to avoid rubbing the rash.
• Use a cool, damp cloth on the skin to soothe pain and itching.
• Keep the skin clean and dry, but do not burst any blisters.
• Ask your pharmacist about gentle pain relief if the rash is painful, but only use it if your doctor says it is safe for you.

Medical treatments

Your doctor may prescribe corticosteroid medicines, which may be applied as a cream, taken as tablets, or given as an injection. These drugs quickly calm the inflammation. If steroids are not suitable or do not work, other medicines that calm the immune system may be considered. Any medicine that might have triggered the condition may be stopped or changed. Your doctor will explain the options and the possible side effects so you can decide together.

When is surgery considered?

Surgery is not used to treat Sweet syndrome itself. A small skin biopsy is often needed for diagnosis, but that is a minor procedure, not surgery. In very rare cases, if an underlying issue like an abscess or infected tissue is found, it may need drainage or other intervention.

Living with this condition

With treatment, most people feel better within a few weeks. You may be tired while the inflammation settles, so plan for rest. Keep a note of your symptoms and any possible triggers, such as a new medicine or a recent illness. This can help your doctor care for you. Since Sweet syndrome can come back, stay in touch with your care team and report any new skin changes early.

Lifestyle tips

• Keep a symptom diary to notice patterns.
• Drink plenty of fluids to stay hydrated.
• Try light activity, like short walks, if you feel up to it.
• Protect your skin from sunburn, which can sometimes worsen rashes.
• Try to keep a regular sleep schedule to help your immune system recover.

Diet and exercise

No specific diet is known to cure Sweet syndrome. Eating a balanced diet with lots of fruits, vegetables, and whole grains can support your overall health. If you and your doctor suspect a particular food or medicine is a trigger, you can work together to test that. Gentle exercise may improve your mood and energy, but avoid intense exercise during an active flare.

Mental health and emotional wellbeing

Living with a visible rash and an unexplained illness can be stressful. You might feel anxious, embarrassed, frustrated, or low. These feelings are normal. Sweet syndrome is not your fault and not contagious. Talking to a counsellor or therapist, joining a support group, or opening up to trusted friends and family can help. If you are struggling, reach out to your GP or a local mental health service for support.

Prevention

Because the exact cause is not fully understood, there is no sure way to prevent Sweet syndrome. If you know a medicine triggered it, avoiding that medicine helps. Treating underlying conditions, such as infections or inflammatory bowel disease, may also lower your risk. If you have had Sweet syndrome before, tell your doctor about any new symptoms early so it can be treated quickly.

Vaccines

There is no vaccine to prevent Sweet syndrome. However, keeping your vaccinations up to date – like the flu vaccine – may help avoid infections that could trigger it. Discuss vaccination with your healthcare provider.

Screening programmes

There is no routine screening test for Sweet syndrome. If you have an underlying condition that increases your risk, your doctor will monitor you as part of your usual care.

Complications

If left untreated

• The rash can become larger, more painful, and may develop blisters or open sores that can get infected.
• High fever and widespread inflammation can make you feel very unwell.
• Sweet syndrome can be a warning sign of an underlying condition, such as a blood cancer, that needs investigation and treatment.
• Very rarely, inflammation can affect other organs, such as the eyes, lungs, or kidneys.

Long-term outlook

The outlook is generally very good. With appropriate treatment, most people see their rash and fever clear within a few weeks. Sweet syndrome can recur, especially if the underlying cause is not addressed, but many people have only one episode. If an underlying condition is found, treating it often leads to a longer-lasting improvement. Your care team will help you manage the condition and keep you as comfortable as possible.

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