Sweet Syndrome — Know It All!


All you need to know about Acute Febrile Neutrophilic Dermatosis.

Know your ailment well, so you can manage it better!!

Here we come with Sweet Syndrome today!

Sweet Syndrome 

What is Acute Febrile Neutrophilic Dermatosis?

Sweet Syndrome is medically known as Acute Febrile Neutrophilic Dermatosis.

Sweet syndrome is a rare disorder characterised by fever and sudden onset of rash, consisting of multiple bumps or lesions that are tender, red or bluish-red. Usually, these lesions are on the arms, legs, trunk, face, or neck. In some cases, the musculoskeletal system, such as inflammation of the joints (arthritis), the eyes, such as inflammation of the conjunctiva or the membrane lining the eyes (conjunctivitis), and the inner organs may be involved in additional systems of the body. The disorder occurs by itself for no known reason (idiopathic Sweet syndrome) in the majority of affected individuals; this is also known as classical Sweet syndrome. Less often, underlying cancer (malignancy), usually blood (hematologic) cancer such as certain types of leukaemia, can be associated with the disorder; this is referred to as Sweet Syndrome associated with malignancy. The disorder can also result in a reaction to certain drugs, particularly a drug known as the stimulating factor of granulocyte-colony; this is known as the Sweet syndrome induced by the drug. Corticosteroids treat the sweet syndrome.

The sweet syndrome was first described by Dr Robert Douglas Sweet in medical literature in 1964. The disorder is classified as neutrophilic dermatosis, a general term used to describe a group of skin disorders characterised by the neutrophil accumulation in the skin. Neutrophils are a specific type of white blood cell that by surrounding and killing bacteria that enter the body, is instrumental in fighting off infection. Neutrophils accumulate in the dermis in Sweet syndrome, a thick layer of tissue just below the outer layer of the skin (epidermis).

Sweet Syndrome 

What causes Sweet Syndrome?

There is no complete understanding of the exact cause of Sweet syndrome. The disorder is most likely caused by a number of complex factors, including immunological and environmental factors. Some researchers speculate that Sweet syndrome occurs as an allergic reaction to an unknown agent (reactive process). In such cases, the immune system is over-sensitive or hypersensitive to a particular agent, such as a bacterial or viral infection, cancer, or a certain type of drug.

Dysregulation of cytokines may also play a role in the disorder‘s development. Cytokines are specialised proteins secreted from certain cells of the immune system which either stimulate the function of other cells of the immune system or inhibit it. If these cytokines fail, overstimulation of the immune system in response to a specific agent may result.

There is an upper respiratory infection, gastrointestinal infection, or influenza-like illness in many people with classic Sweet syndrome that precedes their skin lesions by one to three weeks. In women, during pregnancy, classic Sweet syndrome may occur. Sweet syndrome, associated with pregnancy, typically occurs in the first or second trimester. There does not appear to be any foetal risk and, with subsequent pregnancies, the syndrome may recur.

In some cases, autoimmune and inflammatory disorders such as inflammatory bowel disease may also be associated with the classic Sweet syndrome: ulcerative colitis or Crohn’s disease. (Choose the specific disorder name as your search term in the Rare Disease Database for more information on these disorders.)

After certain medicines, drug-induced Sweet syndrome develops, the most commonly associated drug is known as the stimulating factor of granulocyte-colony. This drug is used to stimulate neutrophil manufacturing. A wide variety of additional drugs have been associated with Sweet syndrome, although less often.

Malignancy-associated Sweet syndrome is most commonly associated with blood cancers such as leukaemia and lymphoma and solid tumours including breast cancer.

More research is necessary to determine the exact underlying mechanisms that contribute to and ultimately cause the development of Sweet syndrome.

Sweet Syndrome 

What are the symptoms of Sweet Syndrome?

Common Symptoms:

  • High or moderate fever
  • Tiredness and malaise (feeling unwell)
  • Skin lesions
  • Sore eyes and/or mouth ulcers
  • Aching joints
  • Headache

The sudden onset of tender or painful bumps (nodules or papules) on the arms, legs, face or neck is the major symptom of Sweet syndrome. They may occur on the thighs and trunk as well. Papules are strong and increase lesions; nodules are slightly larger and may extend into the skin more deeply. These initial lesions usually have a diameter of several millimetres to centimetres, but sometimes a diameter of up to one inch, flat or slightly elevated, irregularly shaped, and inflamed. They tend to slowly grow, eventually joining (coalescing) together to form larger, irregular plaques. It may develop small pus-filled blisters (pustules).

Neutrophils may accumulate in some individuals in the fatty layer of tissue just below the skin ( subcutaneous fat) rather than in the dermis. Often, affected people develop reddish (erythematous) skin discolouration and small bumps (nodules) on the skin. Most often, the arms and legs are affected.

Fever, fatigue, headaches, a general feeling of ill health (malaise), muscle pain (myalgia), and joint inflammation and pain (arthritis and arthralgia) are also experienced by individuals with Sweet syndrome. The development of skin symptoms can be preceded by fever for days or weeks.

Most organ systems of the body can potentially be affected by Sweet syndrome. Outside of the skin, the most common organ system involved is the eyes. Inflammation of the conjunctiva, the delicate membrane lining the eyes (conjunctivitis), or inflammation of the thin layer of tissue (episclera) covering the whites of the eyes (episcleritis) can develop in affected individuals. Other symptoms may occur less frequently, including the formation of limbus bumps, which are the edges of the cornea and the whites of the eyes (limbal nodules), glaucoma, iris inflammation, which is the coloured portion of the eye (iritis), and corneal inflammation and ulceration (peripheral ulcerative keratitis).

The sweet syndrome occurs without any underlying disorder in most people. In these individuals with classic Sweet syndrome, an upper respiratory tract or gastrointestinal system infection usually follows the onset of the disorder.

Sweet syndrome is associated less often with malignancy, most often with blood-impacting malignancies (haematological malignancies), such as certain types of leukaemia, and rarely with genitourinary and gastrointestinal tract cancers. Individuals with Sweet syndrome associated with malignancy may have lesions affecting the mucous membranes of the mouth (oral mucosa) in some instances.

The skin (cutaneous) symptoms of drug-induced Sweet Syndrome are comparable to those seen in the classical form.

Affected Populations:

By some estimates, Classical Sweet Syndrome in adults affects women more often than men by as much as 15:1. In malignancy-associated or medication-induced Sweet syndrome, this female preponderance has not been seen. Classical Sweet Syndrome usually affects women between 30–50 years of age, but can be seen in people, including children, of any age. In children, there is no gender predominance seen. In the medical literature, several hundred individuals have been reported with Sweet syndrome. In the medical literature, only approximately 80 children were reported.

What are the risk factors of Sweet Syndrome?

Sweet’s syndrome is uncommon, but certain factors increase your risk, including:

  • Sex. In general, women are more likely to have Sweet’s syndrome than are men.
  • Age. Though older adults and even infants can develop Sweet’s syndrome, the condition mainly affects people between the ages of 30 and 60.
  • Cancer. Sweet’s syndrome is sometimes associated with cancer, most often leukaemia. Sometimes, Sweet’s syndrome may be associated with a solid tumour, such as breast or colon cancer.
  • Other health problems. Sweet’s syndrome may follow an upper respiratory infection, and many people report having flu-like symptoms before the rash appears. Sweet’s syndrome can also be associated with inflammatory bowel disease.
  • Pregnancy. Some women develop Sweet’s syndrome during pregnancy.
  • Drug sensitivity. Sweet’s syndrome may result from sensitivity to medication. Drugs linked to Sweet’s syndrome include azathioprine (Azasan, Imuran), granulocyte colony-stimulating factor, certain antibiotics and some nonsteroidal anti-inflammatory drugs.

What are the complications of Acute Febrile Neutrophilic Dermatosis?

The skin lesions are at risk of becoming infected. Follow the recommendations of your doctor to look after the affected skin.

In cases where cancer is associated with Sweet‘s syndrome, lesion eruptions may be the first sign of cancer, either occurring or recurring.

Sweet Syndrome 

How is Acute Febrile Neutrophilic Dermatosis diagnosed?

By simply looking at the lesions, your dermatologist might be able to diagnose Sweet‘s syndrome. But you will probably have certain tests to rule out conditions with similar symptoms and to look for the underlying cause. Such tests include:

  • Blood Tests. Your blood sample may be sent to a laboratory where an unusually large number of white blood cells and certain blood disorders are checked.
  • Skin Biopsy. A small piece of affected tissue may be removed by your doctor for examination under a microscope. In order to assess whether it has the characteristic abnormalities of Sweet‘s syndrome, the tissue is analysed.
Sweet Syndrome 

What is the treatment for Acute Febrile Neutrophilic Dermatosis?

Sweet‘s syndrome, without treatment, may go away. But medications can significantly speed up the process.

Corticosteroids, which come in a variety of forms, are the most common medications used for Sweet‘s syndrome, including:

Tablets: Oral corticosteroids work very well, such as prednisone, but will affect your whole body. You would also need to take oral corticosteroids because you just have a few lessons. Long-term use, such as weight gain, insomnia and weakened bones, can cause side effects.

Ointments or creams. Usually, these preparations affect only the portion of the skin where they are applied, but they can cause thinning skin.

injections. Another alternative is to inject a small amount of corticosteroid into each lesion right away. For people who have a large number of lesions, this may be less feasible.

Other drugs for Sweet‘s syndrome are also prescribed, usually for people who do not handle long-term corticosteroid use well. Some of the drug alternatives to corticosteroids that are more widely prescribed are:

  • Dapsone
  • Potassium iodide
  • Colchicine


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Sweet Syndrome