General description

Sweet disease is an acute systemic inflammatory condition characterized by fever, neutrophilia, and painful edematous erythema of the skin. The exact cause of the disease is unknown, but it is often associated with preceding infectious diseases, inflammatory diseases, malignant tumors, and hematopoietic disorders. It is hypothesized that these underlying conditions trigger the release of cytokines, promoting neutrophil proliferation and infiltration, leading to the development of Sweet disease.

Typically, the onset of Sweet disease is preceded by severe fever, followed by the appearance of tender, raised, and erythematous skin lesions with well-defined borders. These lesions commonly occur on the face, neck, upper extremities, and upper back, resembling erythema nodosum, although Sweet disease lesions are more frequently found on the lower extremities. Joint symptoms and neurological manifestations may also accompany the skin rash.

Sweet disease is strongly associated with HLA-B54, while Behçet's disease is correlated with HLA-B51 and is rare in individuals with HLA-B54.

Neuro-Sweet disease

Sweet disease can indeed manifest with neurological involvement, leading to a subtype known as neuro-Sweet disease. The male-to-female ratio in neuro-Sweet disease is approximately 1.5:1, and most cases occur between the ages of 30 and 60. Additionally, there is a frequent occurrence of positive HLA-Cw1 in patients with neuro-Sweet disease.

Neurological symptoms associated with neuro-Sweet disease encompass a broad spectrum, including headache, impaired consciousness, epilepsy, ocular motility disorders, rigidity of the neck, memory impairment, dysarthria, hemiplegia, mental retardation, ataxia, and involuntary movements.

Radiographic features

Encephalitis

In cases of encephalitis associated with neuro-Sweet disease, asymmetrical and scattered T2WI hyperintensity can be observed in various regions of the central nervous system, including the cerebrum, cerebellum, brainstem, basal ganglia, and thalamus. The presence of contrast enhancement within the lesions may be variable.