Sweet's Syndrome (Acute Febrile Neutrophilic Dermatosis) - Symptoms, Causes & Treatment
Medically reviewed by Dr. Anand S. Urhekar, MD, MD Pathology, Clinical Advisor · Last updated July 2026
A reactive inflammatory condition producing the sudden onset of fever with tender, juicy red or violet plaques on the face, neck, upper trunk and arms. It may follow an infection, be triggered by medication, accompany inflammatory bowel disease, or signal an underlying blood cancer.
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Quick Answer
Sweet's syndrome is the abrupt onset of fever with painful, raised, juicy red plaques on the face, neck and arms, caused by neutrophils flooding the skin. Triggers include recent infection, medications such as G-CSF, inflammatory bowel disease, pregnancy and underlying haematological cancer. It responds dramatically to oral corticosteroids, usually within days, but requires investigation for an underlying cause.
Symptoms
- Sudden tender red or violet plaques with a juicy, oedematous look
- Fever and feeling unwell
- Face, neck, upper chest and arms
- Sometimes pseudo-blistering appearance
- Joint pain, eye inflammation and mouth ulcers in some cases
Causes & Risk Factors
- Recent upper respiratory or gastrointestinal infection
- Medications, especially G-CSF, azathioprine and some antibiotics
- Inflammatory bowel disease and other autoimmune disease
- Pregnancy
- Underlying malignancy, particularly acute myeloid leukaemia
Treatment & Management
- Oral corticosteroids — usually rapid response within 48 hours
- Investigation for infection, drug triggers and malignancy
- Potassium iodide or colchicine as steroid-sparing options
- Dapsone or ciclosporin for recurrent disease
- Treating any identified underlying cause
When to See a Doctor
Seek prompt medical review for fever with new painful raised skin plaques. Blood tests and often a skin biopsy are needed, and an underlying cause must be excluded.
Frequently Asked Questions
Does Sweet's syndrome always mean cancer?
No. Most cases are reactive to infection or medication. However, around 20% are associated with an underlying malignancy, so screening blood tests and clinical assessment are standard.
How quickly does treatment work?
Oral corticosteroids typically produce dramatic improvement in fever and skin pain within one to three days, though the course is tapered over weeks to prevent relapse.
Related Conditions
Medical References
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Medical Disclaimer: This information is for educational purposes only and is not intended as medical advice. The content on this page should not be used to diagnose or treat any health problem. Always consult with a qualified healthcare professional for proper medical evaluation, diagnosis, and treatment of your condition.