What is Sweet Syndrome?

Sweet syndrome, identified by Robert Douglas Sweet in 1964, is an acute medical condition that affects the skin, causing fever and inflammation. It’s a type of disorder called ‘neutrophilic dermatosis’, a group of skin conditions that are not infectious, but involve an increase in a type of white blood cell-called neutrophils-in the skin layers, with or without blood vessel inflammation. Neutrophilic dermatoses could be spontaneous, linked to other disorders, localized or widespread, and may or may not exhibit additional symptoms beyond the skin.

Sweet syndrome is a part of the non-blood vessel inflammation group of neutrophilic dermatosis disorders, along with others like pyoderma gangrenosum, a type of skin ulcer; pustular psoriasis, a form of psoriasis; and various other conditions.

This syndrome typically begins abruptly with clear, painful skin spots or bumps along with fever, joint pain, eye inflammation, headaches, and, less frequently, sores in the mouth or genital area. It might also show other symptoms affecting parts of the body other than the skin, although these are rare. The objective of treating Sweet syndrome is to lessen the impact of the disease and avoid complications. The preferred initial treatment is systemic or topical corticosteroids if the skin lesions are limited. If corticosteroids cannot be used, drugs like colchicine or dapsone, that reduce inflammation, are viable alternatives.

What Causes Sweet Syndrome?

Sweet Syndrome is a condition that can occur on its own, which is most common, or it can be linked to an underlying condition.

Several types of cancer have been found to be connected with Sweet syndrome. These include several blood disorders such as myelodysplasia, acute myelogenous leukemia, chronic myelogenous leukemia, multiple myeloma, monoclonal gammopathy, lymphoma, and rarely, solid tumors. Sweet syndrome can occur before, during, or after a diagnosis of cancer. It’s also most likely to occur in older people and those with cytopenias, a condition where there is a decrease in mature blood cells. Certain features of Sweet syndrome are also more likely to be associated with cancer, especially myelodysplastic syndrome, a type of cancer where the bone marrow doesn’t produce enough healthy blood cells.

Sweet Syndrome may also occur with several inflammatory and autoimmune diseases. These include inflammatory bowel disease (ulcerative colitis or Crohn disease), rheumatoid arthritis, systemic lupus erythematosus, Sjogren syndrome, Hashimoto thyroiditis, Behcet disease, and dermatomyositis.

Sweet Syndrome has been found to occur one to three weeks after upper respiratory and gastrointestinal infections. It’s also been seen with other infections like HIV, viral hepatitis, tuberculosis, and there have been some reports of it happening with chlamydia infection.

Drug-induced Sweet syndrome is also well-known, with various drugs reported to cause the syndrome. G-CSF is the most common drug reported, but a variety of other drugs including certain antibiotics, blood pressure medications, NSAIDs (nonsteroidal anti-inflammatory drugs), immunosuppressives, antiepileptics, cancer treatments, antipsychotics, and thyroid medicines. In these cases, Sweet syndrome happens after exposure and sometimes re-exposure to the suspected drug and gets better with or without corticosteroid treatment after the drug is stopped.

Pregnancy is related to the development of Sweet syndrome in about 2% of cases. However, the outlook is positive with the condition usually resolving after delivery, and there is no risk of complications or deaths linked to the mother or baby.

Risk Factors and Frequency for Sweet Syndrome

Sweet syndrome is more commonly found in women, with four women affected for every man. Typically, the condition starts to show up between the ages of 30 and 60. However, it can occur in children and the elderly too. Interestingly, Sweet syndrome affects all races equally.

Signs and Symptoms of Sweet Syndrome

Sweet syndrome is usually marked by sudden tender, red patches or lumps on the skin, but it can also have several other symptoms that affect other parts of the body.

For the skin, the discomfort begins abruptly with red, tender lumps or patches of varying sizes, often appearing in a random pattern. These can take on the form of pus-filled bumps, blister-like lesions, and target-like marks. While they can appear anywhere, they’re most common on the upper extremities but can also pop up on the face, neck, chest, back, and lower extremities. Lesions in the mouth or genitals are rare and are sometimes associated with certain blood cancers. Lumps forming beneath the skin are tender and might be mistaken for erythema nodosum. Similarly, a positive reaction to a pricking test, a characteristic of Behcet’s disease, could occur in Sweet syndrome.

As for general symptoms, fever is almost always present, especially if caused by specific medications. However, 10%-20% of cases related to other causes will not present with a fever. Other common symptoms include joint pain, muscular pain, fatigue, general illness, and headaches.

Beyond skin symptoms, Sweet syndrome can affect other parts of the body. 30% to 60% of incidences include joint complications, such as painful joints and non-erosive inflammatory arthritis. Eye inflammation, especially conjunctivitis, is common. Other possible eye-related complications involve inflammation of different parts of the eye, including surface, deep tissues and even the retina. There are also reported cases of the condition affecting other organs, causing inflammation in the heart muscle, multifocal sterile bone inflammation, lung inflammation, pleural effusions (excess fluid around the lungs), and aseptic meningitis (inflammation of the protective layers of the brain and spinal cord not caused by bacterial infection).

To diagnose Sweet syndrome, there are certain criteria the patient needs to meet. The most significant findings include the sudden appearance of tender, painful patches or lumps on the skin and neutrophilic infiltrate found in the skins layer without vasculitis. These two factors must be present for a conclusive diagnosis to be made. In addition to these, at least two additional minor clinical features should be present. They could be a fever higher than 38°C, the illness being preceded by a respiratory or gastrointestinal infection, being associated with inflammatory disorders, cancer or pregnancy, a high white blood cell count with more neutrophils and raised inflammatory markers, and a positive response to corticosteroids.

Testing for Sweet Syndrome

If your doctor suspects you have Sweet syndrome, a skin condition often linked to an immune response, they will run certain laboratory tests. These tests often reveal signs of inflammation in your body, such as elevated levels of C-reactive protein, increased white blood cells, and neutrophilia (a high level of neutrophils, a type of white blood cell). They might also perform a biopsy, which involves taking a small skin sample to examine under a microscope. If it shows sections of thick, swollen skin filled mostly with polymorphonucleocytes (a type of white blood cell) and lymphocytes (another type of white blood cell), this might further support that you have Sweet syndrome.

But making a diagnosis of Sweet syndrome also involves identifying its root cause. For some people, an underlying ailment, such as cancer, might trigger Sweet syndrome. Thus, your doctor might look out for general symptoms of illness including weight loss, swollen lymph nodes, and changes in blood count. They might also recommend age-appropriate cancer screenings for you such as colonoscopy (colon cancer screening), mammogram (breast cancer screening), and PAP smears (cervical cancer screening). For men, checking for testicular and prostate cancer might be considered, and for women, a pelvic ultrasound might be suggested. Imaging tests, like CT scans of your chest, abdomen, and pelvis could also be part of your assessment.

In addition, if you’re a woman of childbearing age, a pregnancy test might be needed as part of your Sweet syndrome work-up. Another important factor is checking if you have an autoimmune disease like systemic lupus erythematosus, rheumatoid arthritis, Sjogren syndrome, or Behcet disease. Even though Sweet syndrome is not usually the first symptom of these diseases, your doctor might consider testing for them if they suspect their presence based on other symptoms they observe.

Treatment Options for Sweet Syndrome

Sweet syndrome is a condition usually highly responsive to steroids and it often resolves on its own. Often, a treatment of steroids, provided orally, can typically help improve the condition over a period of two to four weeks. These steroids can also be applied in a concentrated form directly to the affected area or used as a topical application, especially when the Sweet syndrome is localized or only affects a small area.

If the disease comes back after the initially prescribed course of steroids, there are several alternatives to steroids that may prove beneficial. These alternatives include medications like potassium iodide, colchicine, dapsone, isotretinoin, methotrexate, doxycycline, indomethacin, chlorambucil, and cyclosporine. These medications demonstrate how many different treatment options are available if your initial treatment isn’t successful, or if you cannot tolerate steroids.

When diagnosing Sweet syndrome, doctors have to be careful as its symptoms such as fever, increased white blood cells count, inflammation, and dense clusters of a certain type of white blood cell (neutrophils), can often be confused with infections. Bacterial, fungal and mycobacterial infections need to be ruled out.

Also, the skin lesions of Sweet syndrome can often look like several other skin conditions, such as:

Allergic contact dermatitis
Cellulitis
Behcets disease
Herpes simplex
Hypersensitivity drug reaction
Erythema multiforme
Erythema nodosum
Pyoderma gangrenosum

In addition, Sweet syndrome can be wrongly diagnosed as the following conditions:

Leukocytoclastic vasculitis
Leukemia cutis

What to expect with Sweet Syndrome

Most instances of this condition get better over time, but some may last indefinitely and potentially lead to chronic pain and skin damage. Because this condition might be linked to other diseases, including cancer, how well a person does depends on what’s causing the problem in the first place. Relapses may happen in up to 50% of patients, particularly if they have an ongoing inflammatory condition or a blood cancer.

Possible Complications When Diagnosed with Sweet Syndrome

Normally, if Sweet syndrome is diagnosed promptly and treated correctly, the skin sores can heal without leaving any scars.

Frequently asked questions

The prognosis for Sweet syndrome depends on the underlying cause of the condition. In most cases, the condition improves over time. However, some cases may last indefinitely and potentially lead to chronic pain and skin damage. Relapses may occur in up to 50% of patients, especially if they have an ongoing inflammatory condition or a blood cancer.

Sweet Syndrome can be acquired through several ways, including: - Being linked to an underlying condition such as cancer, inflammatory and autoimmune diseases, infections, drug-induced reactions, or pregnancy. - It can also occur on its own without any underlying condition.

Signs and symptoms of Sweet Syndrome include: - Sudden tender, red patches or lumps on the skin - Discomfort beginning abruptly with red, tender lumps or patches of varying sizes - Lesions taking on the form of pus-filled bumps, blister-like lesions, and target-like marks - Commonly appearing on the upper extremities, but can also occur on the face, neck, chest, back, and lower extremities - Rare occurrence of lesions in the mouth or genitals, sometimes associated with certain blood cancers - Lumps forming beneath the skin that are tender and can be mistaken for erythema nodosum - Positive reaction to a pricking test, characteristic of Behcet's disease, can occur in Sweet Syndrome - Fever, which is almost always present, especially if caused by specific medications - Joint pain, muscular pain, fatigue, general illness, and headaches - Joint complications, such as painful joints and non-erosive inflammatory arthritis (30% to 60% of cases) - Eye inflammation, especially conjunctivitis, and inflammation of different parts of the eye - Inflammation in other organs, including the heart muscle, bones, lungs, and protective layers of the brain and spinal cord - Criteria for diagnosis include the sudden appearance of tender, painful patches or lumps on the skin and neutrophilic infiltrate found in the skin's layer without vasculitis - Additional minor clinical features that can be present include fever, respiratory or gastrointestinal infection preceding the illness, association with inflammatory disorders, cancer or pregnancy, high white blood cell count with more neutrophils and raised inflammatory markers, and a positive response to corticosteroids.

The types of tests that are needed for Sweet Syndrome include: - Laboratory tests: These tests can reveal signs of inflammation in the body, such as elevated levels of C-reactive protein, increased white blood cells, and neutrophilia. - Biopsy: A small skin sample is taken and examined under a microscope to look for sections of thick, swollen skin filled mostly with polymorphonucleocytes and lymphocytes. - General symptom assessment: The doctor will look for general symptoms of illness, such as weight loss, swollen lymph nodes, and changes in blood count. - Cancer screenings: Age-appropriate cancer screenings may be recommended, such as colonoscopy, mammogram, PAP smears, testicular and prostate cancer checks, and pelvic ultrasound. - Imaging tests: CT scans of the chest, abdomen, and pelvis may be done to further assess the condition. - Pregnancy test: If you are a woman of childbearing age, a pregnancy test may be needed. - Autoimmune disease testing: Testing for autoimmune diseases like systemic lupus erythematosus, rheumatoid arthritis, Sjogren syndrome, or Behcet disease may be considered.

The doctor needs to rule out the following conditions when diagnosing Sweet Syndrome: - Bacterial, fungal, and mycobacterial infections - Allergic contact dermatitis - Cellulitis - Behcets disease - Herpes simplex - Hypersensitivity drug reaction - Erythema multiforme - Erythema nodosum - Pyoderma gangrenosum - Leukocytoclastic vasculitis - Leukemia cutis

When treating Sweet Syndrome, the use of steroids can have potential side effects, including weight gain, mood changes, increased appetite, and increased risk of infection. However, if the initial treatment with steroids is not successful or if the patient cannot tolerate steroids, there are alternative medications available that may be beneficial, such as potassium iodide, colchicine, dapsone, isotretinoin, methotrexate, doxycycline, indomethacin, chlorambucil, and cyclosporine. It is important to note that if Sweet Syndrome is diagnosed promptly and treated correctly, the skin sores can heal without leaving any scars.

Dermatologist.

Sweet syndrome is more commonly found in women, with four women affected for every man.

Sweet syndrome is usually treated with steroids, which can be taken orally or applied topically to the affected area. This treatment is typically effective and can improve the condition within two to four weeks. If the disease returns or if steroids are not effective or tolerated, there are several alternative medications that can be used, such as potassium iodide, colchicine, dapsone, isotretinoin, methotrexate, doxycycline, indomethacin, chlorambucil, and cyclosporine.

Sweet syndrome is an acute medical condition that affects the skin, causing fever and inflammation. It is a type of neutrophilic dermatosis, characterized by an increase in neutrophils in the skin layers, with or without blood vessel inflammation.

Benign Lesions of the Skin Corticosteroids Fever Neutrophils Skin Problems And Treatments