Juvenile Idiopathic Arthritis (JIA): This condition is highly suggestive of a rheumatic disease, especially given the recurrent rashes. JIA can present with various symptoms including joint pain, fever, and rash, making it a prime consideration in this scenario.

Systemic Lupus Erythematosus (SLE): SLE is an autoimmune disease that can cause a wide range of symptoms, including rashes, joint pain, and fever. It is more common in females and can present in childhood.
Dermatomyositis: This is an inflammatory disease characterized by skin rash and muscle weakness. The rash can be recurrent and is often accompanied by other symptoms such as fever and joint pain.
Mixed Connective Tissue Disease (MCTD): MCTD is an autoimmune disease that combines features of lupus, scleroderma, and rheumatoid arthritis. It can cause a variety of symptoms including rashes, joint pain, and fever.

Kawasaki Disease: Although more common in younger children, Kawasaki disease can present with fever, rash, and other systemic symptoms. It is crucial to diagnose promptly as it can lead to serious cardiac complications if untreated.
Vasculitis (e.g., Henoch-Schönlein Purpura): Vasculitis refers to inflammation of the blood vessels and can cause a range of symptoms including rashes, joint pain, and abdominal pain. Some forms, like Henoch-Schönlein Purpura, are more common in children and can be serious if not recognized.

Sjögren's Syndrome: This is an autoimmune disorder that primarily affects the glands that produce tears and saliva, but it can also cause rashes and other systemic symptoms. It is less common in children but should be considered in the differential diagnosis of recurrent rashes and suspected rheumatic disease.
Relapsing Polychondritis: A rare autoimmune disorder characterized by recurrent episodes of cartilage inflammation, which can lead to a variety of symptoms including rashes, joint pain, and respiratory issues. It is uncommon in children but should be kept in mind when evaluating recurrent and unexplained symptoms.