Rheumatoid Arthritis (RA): This is a common autoimmune disorder that often presents with symmetric polyarthralgia, particularly affecting the wrists and hands. Morning stiffness lasting more than an hour is a hallmark symptom.

Osteoarthritis (OA): Although OA more commonly affects weight-bearing joints, it can also involve the wrists and hands, especially in older adults. The pain is typically worse with activity and relieved by rest.
Fibromyalgia: Characterized by widespread musculoskeletal pain accompanied by fatigue, sleep, memory, and mood issues. The pain in fibromyalgia can be diffuse and may include the wrists and arms.
Lupus: Systemic Lupus Erythematosus (SLE) is an autoimmune disease that can cause polyarthralgia, among other systemic symptoms like skin rashes, kidney issues, and neurological problems.

Giant Cell Arteritis: Although it primarily affects the temporal arteries, it can cause polymyalgia rheumatica, which includes pain and stiffness in the arms. Missing this diagnosis can lead to blindness if not treated promptly.
Septic Arthritis: An infection within a joint, which is a medical emergency. Symptoms can include sudden onset of pain, swelling, and decreased range of motion in a single joint, but it can progress to multiple joints if not treated.
Lymphoma: Certain types of lymphoma can cause systemic symptoms including polyarthralgia. It's crucial to consider this in the differential due to its potential severity and the need for early intervention.

Relapsing Polychondritis: A rare autoimmune disorder that can cause cartilage inflammation, leading to polyarthralgia among other symptoms like ear and nose cartilage involvement.
Sjögren's Syndrome: An autoimmune disorder that primarily affects the glands that produce tears and saliva but can also cause polyarthralgia and arthritis.
Mixed Connective Tissue Disease (MCTD): A rare autoimmune disorder that combines features of lupus, scleroderma, and polymyositis, often presenting with polyarthralgia and arthritis.