L98.2 Febrile neutrophilic dermatosis [Sweet]

Name of the Condition

• Febrile neutrophilic dermatosis [Sweet]

Summary

Febrile neutrophilic dermatosis, also known as Sweet syndrome, is an acute inflammatory skin condition characterized by painful, erythematous plaques or nodules, often accompanied by fever and neutrophilia. It may occur as a primary idiopathic condition or secondary to underlying malignancies, infections, or inflammatory diseases. The skin lesions typically develop rapidly and can be associated with systemic symptoms.

Causes

The exact cause is not fully understood, but it is thought to involve an abnormal immune response leading to neutrophilic infiltration of the skin. In some cases, it may be triggered by infections (e.g., upper respiratory tract infections), malignancies (especially hematologic cancers), or inflammatory conditions (e.g., inflammatory bowel disease, rheumatoid arthritis). Medications, such as certain antibiotics or granulocyte colony-stimulating factors, have also been implicated as triggers.

Risk Factors

• Recent infection (e.g., respiratory or gastrointestinal)
• Underlying malignancy (particularly hematologic cancers)
• Autoimmune or inflammatory diseases (e.g., rheumatoid arthritis, inflammatory bowel disease)
• Certain medications (e.g., antibiotics, anticonvulsants)
• Pregnancy

Symptoms

• Painful, erythematous plaques or nodules on the skin, often with a pseudovesicular or pustular appearance
• Lesions typically appear on the face, neck, trunk, or extremities
• Fever, malaise, or arthralgias may accompany the skin lesions
• Lesions may ulcerate or resolve spontaneously over weeks

Diagnosis

Diagnosis is based on clinical presentation, laboratory findings, and histopathology. A skin biopsy showing a dense neutrophilic infiltrate in the dermis without evidence of infection or vasculitis is diagnostic. Laboratory tests may reveal elevated white blood cell count (neutrophilia), elevated erythrocyte sedimentation rate, or C-reactive protein. Underlying causes, such as infection or malignancy, should be investigated if suspected.

Treatment Options

• Systemic corticosteroids (e.g., prednisone) are the first-line treatment for rapid symptom relief
• Topical or intralesional corticosteroids may be used for localized lesions
• Dapsone or colchicine may be considered for steroid-sparing or refractory cases
• Treatment of underlying triggers (e.g., infection, malignancy) is essential for secondary cases

Prognosis and Follow-Up

Prognosis is generally good with appropriate treatment, though recurrence is common, especially in cases associated with underlying conditions. Follow-up is recommended to monitor for resolution of lesions, recurrence, or development of associated systemic symptoms. Long-term management may be necessary for patients with chronic or recurrent disease.

Complications

• Recurrence of skin lesions
• Persistent systemic symptoms (e.g., fever, fatigue)
• Association with underlying malignancy or autoimmune disease
• Rarely, ocular or visceral involvement (e.g., lung, kidney)

Lifestyle & Prevention

• Avoid known triggers (e.g., certain medications, infections) when possible
• Maintain good skin hygiene to prevent secondary infections
• Manage underlying conditions (e.g., autoimmune diseases) with appropriate therapy
• Monitor for early signs of recurrence or systemic involvement

When to Seek Professional Help

Seek medical attention if you develop painful, rapidly spreading skin lesions with fever, especially if you have a history of malignancy, autoimmune disease, or recent infection. Prompt evaluation is important to rule out serious underlying causes and initiate treatment.

Tips for Medical Coders

When coding for febrile neutrophilic dermatosis (Sweet syndrome), use ICD-10-CM code L98.2. Ensure documentation supports the diagnosis, including clinical findings (e.g., painful erythematous plaques, fever), laboratory results (e.g., neutrophilia), and any associated underlying conditions. Differentiate from other neutrophilic dermatoses or infectious processes to avoid miscoding.