Sweet syndrome, also known as acute febrile neutrophilic dermatosis, is a rare inflammatory skin condition characterized by its sudden onset. This disorder involves a specific type of white blood cell, called neutrophils, accumulating in the skin. First described in 1964 by Dr. Robert Douglas Sweet. The condition is not contagious and does not represent a form of skin cancer.
Understanding the Manifestations
Sweet syndrome presents with distinct skin lesions. These lesions manifest as tender, red or bluish-red papules, nodules, or plaques that are often swollen. They can have a pseudovesicular or pustular appearance, meaning they might look like blisters or pus-filled bumps. While generally not itchy, these skin lesions are frequently painful. Common locations for these eruptions include the face, neck, arms, and legs, with the trunk being less commonly affected.
Beyond the skin, individuals with Sweet syndrome often experience systemic symptoms. Fever is a frequent accompanying sign. Other common constitutional symptoms include a general feeling of unwellness, aching joints, and muscle pain. Some individuals may also develop eye inflammation and occasionally mouth ulcers.
Underlying Associations
While Sweet syndrome can occur without an identifiable cause, it frequently develops in conjunction with other underlying health issues. The condition is considered a reactive dermatosis, implying it is a skin reaction to a deeper systemic process within the body.
Various conditions have been linked to the development of Sweet syndrome. Malignancies, particularly those affecting the blood such as acute myeloid leukemia and myelodysplastic syndromes, are notable associations. The skin manifestations can appear before, during, or after the diagnosis of these cancers. Infections, such as upper respiratory tract infections, are also common triggers.
Certain medications can also induce Sweet syndrome, with granulocyte-colony stimulating factor (G-CSF) being a well-recognized example. Other drugs, including trimethoprim-sulfamethoxazole and minocycline, have also been reported as triggers. Autoimmune or inflammatory conditions like inflammatory bowel disease, rheumatoid arthritis, systemic lupus erythematosus, and Sjogren syndrome are further associations.
Identifying the Condition
Diagnosing Sweet syndrome involves a comprehensive approach that combines clinical observation with laboratory and histological findings. A healthcare provider will assess the characteristic tender skin lesions and the presence of associated systemic symptoms. Blood tests are typically performed to check for signs of inflammation and changes in blood cell counts.
These tests reveal an elevated white blood cell count, particularly an increase in neutrophils. Inflammatory markers are also elevated. A skin biopsy is an important step for confirming the diagnosis. Microscopic examination of the tissue sample shows a dense accumulation of neutrophils in the dermis, the layer of skin beneath the outer epidermis, without evidence of true vasculitis.
Treatment Options
Sweet syndrome responds well to treatment, with symptoms improving rapidly once therapy is initiated. Systemic corticosteroids are considered the primary treatment option. These medications work by reducing inflammation throughout the body and are prescribed as an initial high dose that is gradually tapered down to prevent recurrence.
For individuals who cannot tolerate corticosteroids or do not respond adequately, alternative medications are available.
Potassium iodide
Colchicine
Dapsone
Indomethacin
In some situations, other immunosuppressive agents may also be considered. If an underlying associated condition is identified, treating that condition can significantly contribute to the resolution of Sweet syndrome and may help prevent future episodes.