There is a saying, "If you have met one child with autism, you have met one child with autism." This reinforces the concept that autism is different in each child; that each child is unique and therefore how autism appears in each child is different. That said, there are some common triggers for meltdowns. Understanding these might help you better understand your child's meltdowns and diffuse the situation, sometimes before it starts.
Sensory overload - Children with autism are often sensitive to sensory stimulation. When in places or situations (such as a store), they can feel assaulted by the noises, colors, lights and activity going on all around them. They might feel fear, panic or simply be at a point where they can't process any additional stimuli.
Frustration - Because children with autism frequently have trouble managing emotion, when someone doesn't occur the way they perceive it should, frustration levels rise. Without a way to regulate their emotions, the frustration and anger boil over.
Difficulty communication - As one of the main symptoms of autism, difficulty communicating can easily lead to meltdowns. When your child can't express his thoughts, either because he is non-verbal or because the words don't come out right, it can cause frustration.
Information overload - Much like sensory overload, when information is coming at your child from many different directions or coming too quickly, your child might react with a meltdown. Children with autism frequently need more time to process information and when not given that time to process each piece, they can become quickly overwhelmed. Trying to multitask or being asked to multitask can lead to information overload.
Changes in routine - Children with autism thrive when they know what to expect and when to expect it. Sudden changes can set off feelings of panic.
Not understanding expectations or not believing they can live up to expectations - This often occurs in social situations. Children, especially older children, often want to interact with others, they want to be accepted and liked but know they aren't very good in these situations. When they don't understand what is expected of them in social situations or are afraid of "failure" meltdowns can occur.
Most of these "triggers" are based in fear. Children with autism often live in a state of anxiety. They need their world to feel safe and secure. When it doesn't, because of changes in their daily routine, being overwhelmed or not being able to communicate their needs, their anxiety levels rise and a meltdown is their way of letting you know they can't handle the current situation. The risk of a meltdown goes up when your child is overly tired, hungry or already feeling stressed from another situation.
Pay attention to your child's meltdowns and what happened in the moments leading up to it. Try to narrow down which triggers your child has difficulty dealing with. Remember, the ones listed here are some common triggers but that doesn't mean they are the only ones. Your child might have meltdowns for different reasons. The more you learn about what your child is trying to tell you, however, the more you can help him cope and lessen the meltdowns.
For more information:
Meltdowns and Tantrums Oh My!
Children with Autism: Taking the Meltdowns out of Haircuts
10 Strategies for Calming a Child with Autism
When is a Temper Tantrum Just a Temper Tantrum? Or is it Time to Get Help?
Parenting Aspies: Meltdowns in Public