OVERVIEW

What is Sweet syndrome?

Sweet syndrome, also known as Acute Febrile Neutrophilic Dermatosis, is a rare allergic skin disease with an unclear specific cause. Some patients may have accompanying malignancies or infections. Symptoms mainly include fever and the appearance of red or purplish-red papules, plaques, or nodules on the skin, which may resemble blister-like protrusions and are tender to the touch. These lesions often occur asymmetrically on the upper limbs, face, and neck. Treatment typically involves immunosuppressive therapies such as corticosteroids.

Is Sweet syndrome common?

It is a relatively uncommon skin disorder.

SYMPTOMS

What are the manifestations of Sweet's syndrome?

• The typical presentation is the sudden appearance of painful, non-itchy red or purplish-red papules, plaques, or nodules on the skin. These lesions commonly affect the face, upper limbs, and neck in an asymmetrical distribution. They may gradually enlarge and merge, with raised edges resembling clear blisters (pseudo-vesicles), which feel solid to the touch. No scarring remains after resolution.

• Additionally, oral mucosal ulcers, conjunctivitis, scleritis, and kidney-related symptoms (such as proteinuria and hematuria) may occur.

• Fever, often exceeding 38°C, may precede the rash or coincide with it, accompanied by joint pain, headache, muscle pain, etc.

CAUSES

What are the causes of Sweet's syndrome?

The exact cause is unknown. Most cases are spontaneous, but some occurrences of Sweet's syndrome are associated with factors such as malignancy or infection.

Is Sweet's syndrome hereditary?

It has a certain degree of heritability.

Who is most commonly affected by Sweet's syndrome?

It predominantly occurs in middle-aged women and is more frequently observed in summer.

Additionally, Sweet's syndrome often appears in cancer patients, particularly those with hematologic malignancies. It is also relatively common in cases accompanied by upper respiratory infections.

DIAGNOSIS

What tests may be needed for the diagnosis of Sweet syndrome?

Routine tests include blood tests, urinalysis, liver and kidney function tests, electrocardiogram, chest X-ray, abdominal ultrasound, etc. Immunological tests are also required, specifically including antinuclear antibodies, immunoglobulins, complement, tuberculosis-related tests, and tumor marker tests.

Which diseases can Sweet syndrome be easily confused with?

• Erythema nodosum, which is more common in young and middle-aged women, has no pseudovesicles on the surface, and the erythema mostly appears on both lower limbs. The pathological findings also differ.

• Erythema multiforme, where the center of the erythema may have blisters or erosions but is not painful. The pathological findings also differ.

TREATMENT

Which department should I visit for Sweet syndrome?

Dermatology.

How is Sweet syndrome treated? How long does treatment take?

• Some patients may improve without treatment and leave no scars, but recurrence is common.

• For severe cases, immunosuppressive therapy is recommended, with systemic glucocorticoids as the first-line treatment. Potassium iodide and colchicine are also commonly used. Medication should be maintained for at least 2–4 weeks.

Do Sweet syndrome patients need follow-up visits?

Yes, follow-up every two weeks to monitor for recurrence.

Can Sweet syndrome be completely cured?

• Many patients recover spontaneously without treatment and leave no scars.

• For severe cases, to prevent secondary infection of skin lesions and accelerate recovery, glucocorticoids or potassium iodide may be used. Proper treatment can achieve a cure, but recurrence is possible.

• The outcome also depends on underlying conditions. If accompanied by malignancy, Sweet syndrome may be harder to control.

Is Sweet syndrome prone to recurrence?

Recurrence is possible. For Sweet syndrome associated with tumors, infections, or other diseases, the risk of recurrence is higher, requiring management of the underlying condition.

DIET & LIFESTYLE

What should patients with Sweet syndrome pay attention to in daily life and diet?

No special precautions are needed. Just avoid intentionally damaging the pseudovesicles on the skin erythema.

Will Sweet syndrome leave scars?

No scars remain after resolution, although skin pigmentation changes may take several months to fade.

PREVENTION

How to Prevent Sweet Syndrome?

Actively treat the underlying disease. Since Sweet syndrome may be caused by genetics, prenatal check-ups should be actively conducted during pregnancy.