The exact cause of Sweet's syndrome isn't always known. In some people, it's triggered by an infection, illness or certain medications. Sweet's syndrome can also occur with some types of cancer.
Most often, Sweet's syndrome will clear on its own in a few months or once the underlying cause is resolved or eliminated. Healing is much more rapid with treatment.
Other signs and symptoms of Sweet's syndrome may include:
- Moderate to high fever preceding the skin lesions
- Pink eye (conjunctivitis) or sore eyes
- Aching joints and headache
- Mouth ulcers
When to see a doctorSweet's syndrome is rare. When it occurs, it often develops after an upper respiratory tract infection. If you develop a red rash that quickly grows in size soon after a bout with strep throat or another upper respiratory infection, see your doctor for appropriate treatment. Although the rash may eventually disappear without treatment, the right medication can make the rash go away in just a few days.
Sweet's syndrome may also be a reaction to a more serious condition, such as leukemia, or to certain medications.
Although Sweet's syndrome may be associated with infections, the condition itself isn't infectious. Sweet's syndrome is typically divided into three categories, depending on its associations:
Idiopathic (classical). In most cases, the cause of Sweet's syndrome isn't known (idiopathic). Idiopathic Sweet's syndrome predominantly affects women between the ages of 30 and 50, and is often preceded by an upper respiratory or gastrointestinal infection. It's also been associated with pregnancy and inflammatory bowel disease.
Malignancy-associated. In about 20 percent of cases, Sweet's syndrome is associated with cancer (malignancy), most often acute leukemia. A few cases may be associated with a solid tumor, such as breast or colon cancer. Sweet's syndrome can occur as an early sign of a cancer, after diagnosis or as a sign of a recurrence. Fever is often present but skin lesions typically aren't preceded by an upper respiratory infection, as is the case with idiopathic Sweet's syndrome. Malignancy-associated Sweet's syndrome appears to affect men and women equally but among older adults, it's more likely to occur in women.
Drug-induced. Although uncommon, Sweet's syndrome may occur as a reaction to a medication, most commonly to granulocyte colony-stimulating factor, a hormone preparation designed to increase your white blood cell count. Other medications associated with Sweet's syndrome include certain antibiotics, oral contraceptives, diuretics and anti-epileptic drugs, among others. Once the offending drug is discontinued, Sweet's syndrome usually goes away.
Sweet's syndrome is uncommon, but certain factors increase your risk, including:
Being a woman. Women are far more likely to have idiopathic Sweet's syndrome than men are.
Being between 30 and 50 years of age. Though older adults and even infants can develop Sweet's syndrome, the condition mainly affects women between the ages of 30 and 50.
Having other health problems. Sweet's syndrome often follows an upper respiratory infection, and many people report having flu-like symptoms before the rash appears. Sweet's syndrome can also be associated with a number of other illnesses, including inflammatory bowel disease, certain systemic infections and cancer.
Being pregnant. Some pregnant women develop Sweet's syndrome during their first or second trimester. In these cases, the condition usually clears without treatment.
A previous history of the condition. Sweet's syndrome tends to recur. About one-third of people who have had Sweet's syndrome once get it again.
There is a risk of the skin lesions becoming infected. Follow your doctor's recommendations for caring for the affected skin. The most challenging aspect of Sweet's syndrome may be in dealing with recurrences, which occur in about a third of cases. Signs and symptoms may reappear, especially if treatment is tapered off too quickly. Be certain to follow your treatment plan exactly as your doctor recommends.
Preparing for your appointment:
Your family doctor or general practitioner is likely to refer you to a dermatologist for diagnosis and treatment of Sweet's syndrome. If tests reveal an underlying condition, you'll also be referred to the appropriate specialist, such as a gastroenterologist or oncologist.
Because appointments can be brief and there's often a lot of ground to cover, it can help to be well prepared. Here are some tips to help you get ready for your appointment and what to expect from your doctor.
What you can do...Write down all your signs and symptoms — even those that seem unrelated to your rash. Sweet's syndrome can be a sign of several illnesses, so it's important that your doctor know all of your symptoms. Include key personal information, such as major stresses or recent life changes. Make a list of all medications, including vitamins, herbs and over-the-counter drugs, that you're taking. Even better, take the original bottles and a written list of the dosages and directions. If possible, take along a family member or friend. It can be difficult to absorb all the information provided to you during an appointment. The person who accompanies you may remember something that you forgot or missed.
Write down questions that you want to ask your doctor. Don't be afraid to ask questions or to speak up when you don't understand something your doctor says. Start with the problems that concern you most. If you run out of time, ask to speak with a nurse or physician's assistant or leave a message for your doctor.
If you have symptoms of Sweet's syndrome, questions you may want to ask include:
What might be causing my rash?
What tests do I need to confirm the diagnosis?
Is this condition temporary or chronic?
What is the best course of action?
What are the alternatives to the primary treatment approach that you're suggesting?
I don't like the idea of taking steroids. Are there other medications you can prescribe?
Is there a generic alternative to the medicine you're prescribing me?
What if I just wait to see if my signs and symptoms go away on their own?
What to expect from your doctorYour doctor is likely to ask you a number of questions, such as:
When did your symptoms start?
Did they come on suddenly or gradually?
What did the rash look like when it first appeared?
Is the rash painful?
What, if anything, makes it better?
What, if anything, makes it worse?
Were you sick before the rash started?
Do you have other symptoms that started about the same time?
What medications do you take?
Tests and diagnosis
Your dermatologist can usually diagnose Sweet's syndrome simply by looking at the lesions. But you're likely to have certain tests to rule out conditions that have similar symptoms and to search for the underlying cause.
These tests include:
Blood tests. A small sample of your blood may be sent to a laboratory where it's checked for an unusually large number of white blood cells and certain blood disorders.
Tissue sample. Your doctor may remove a small piece of affected tissue (biopsy) for examination under a microscope. The tissue is analyzed to determine whether it has the characteristic abnormalities of Sweet's syndrome. The area where the sample is taken is numbed, and a small piece of skin is removed with an instrument that looks like a small cookie cutter — a procedure called a punch biopsy. You're not likely to need stitches, and the incision should heal without scarring.
Treatments and drugs
Left untreated, Sweet's syndrome not associated with a more serious condition may disappear on its own within one to three months. Medications can improve skin lesions and associated symptoms in just two or three days, with the worst of the lesions disappearing within one to four weeks. This is true even for malignancy-associated Sweet's syndrome, although treatment or remission of the associated cancer will help, too.
With or without treatment, the lesions rarely leave a mark or scar when they eventually disappear. Your doctor may advise continuing treatment because recurrence of the condition is common.
Medications Systemic corticosteroids (prednisone or prednisolone) are generally very effective in treating Sweet's syndrome. You typically take these oral anti-inflammatory medications for about four to six weeks. Topical corticosteroids may be used to provide immediate relief of swelling.
Other first line medications your doctor may use include potassium iodide therapy, which you take as an oral tablet or as drops, and colchicine, which has anti-inflammatory properties. Follow your doctor's instructions exactly when taking these medications and be sure your doctor knows about any other medications you're taking, to avoid harmful drug interactions.
Lifestyle and home remedies
If you have Sweet's syndrome, it's important to treat your skin gently. These steps can help reduce additional injury to the skin:
Avoid injury to your skin. Wear protective clothing if you think you might injure or damage your skin.
Apply sunscreen. Use sunscreen with a sun protection factor (SPF) of 15 or greater before you head outdoors.
Farhi D, et al. The neutrophilic dermatoses. Dermatology Nursing. 2008;20:274.
Moschella SL. Neutrophilic dermatoses. http://www.uptodate.com/home/index.html/. Accessed April 5, 2010.
Sweet's syndrome: A dermatologic condition associated with fever and frequently confused with an infectious process. In: Mandell GL, et al. Mandell, Douglas, and Bennet's Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa.: Churchill Livingstone Elsevier; 2010. http://www.mdconsult.com/book/player/book.do?method=display&type=bookPage&decorator=header&eid=4-u1.0-B978-0-443-06839-3..00052-7--s0060&uniq=193269557&isbn=978-0-443-06839-3&sid=978680989#lpState=open&lpTab=contentsTab&content=4-u1.0-B978-0-443-06839-3..00052-7--s0060%3Bfrom%3Dtoc%3Btype%3DbookPage%3Bisbn%3D978-0-443-06839-3. Accessed April 5, 2010.
Cohen PR. Sweet's syndrome — A comprehensive review of an acute febrile neutrophilic dermatosis. Orphanet Journal of Rare Diseases. 2007;2:34.
Franks AG Jr. Skin manifestations of internal disease. Medical Clinics of North America. 2009;93:1265.
Colchicine: Drugdex Evaluations. Micromedex Healthcare Series. http://www.micromedex.com. Accessed April 5, 2010.
June 24, 2010
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