Sensory Processing Disorder (SPD): This condition is characterized by difficulties in processing and integrating sensory information from the environment, which can lead to overstimulation from loud noises. It is a common condition in children and can present with a range of symptoms, including hypersensitivity to sound.

Autism Spectrum Disorder (ASD): Children with ASD often have sensory sensitivities, including hypersensitivity to loud noises, which can cause overstimulation. While not all children with ASD will exhibit this symptom, it is a common feature of the disorder.
Anxiety Disorder: Some children may develop anxiety in response to loud noises, leading to overstimulation. This could be a specific phobia, such as phonophobia (fear of loud sounds), or a more generalized anxiety disorder.
Attention Deficit Hyperactivity Disorder (ADHD): Children with ADHD may have difficulties with sensory regulation, including hypersensitivity to certain sounds, which can contribute to overstimulation.

Meniere's Disease: Although rare in children, Meniere's disease can cause hypersensitivity to sound and should be considered, especially if accompanied by other symptoms like vertigo or hearing loss.
Traumatic Brain Injury: A history of head trauma could lead to hypersensitivity to noise as part of a broader set of symptoms related to the injury.

Williams Syndrome: A genetic disorder that can include hypersensitivity to sound among its many features.
Fragile X Syndrome: The most common cause of inherited intellectual disability, which can also include sensory sensitivities.
Hyperacusis: A condition characterized by an increased sensitivity to certain frequency and volume ranges of sound, which can be debilitating.