Absolutely! But not just your ASD child's illnesses. Autistic children can pick up your emotions when you are going through illnesses or stressors of your own. If your child is becoming increasingly aggressive for reasons you're not aware of...ask yourself: Is anyone she comes into contact with ill or emotionally overwhelmed? (more than normal...as being a parent of an ASD child is it's own emotionally overwhelming experience.)But kudos to you...for noticing that illness is a trigger. Some parents don't even realize that there may be a correlation.

Lukas' pain tolerance is so high that we often can't tell he has an ear infection until his eardrum has ruptured, and even then it's not because he outright complains about it but because he has fluid running out of his ear. Gross, I know. But if we watch him with his older NT brother (who is immeasurably patient with Lukas), he does tend to lash out on his older brother for seemingly no reason. So now we know that is an indirect symptom - if he starts swatting at his brother for no reason, check for new teeth or inflamed ear canals.

My son is always unbearable before he gets sick. His aggression starts days before the first symptom of the illness everytime.

Definitely. I see alot more aggressive behaviors and also ocd type things every time he gets sick.

Our diagnosing psychiatrist told us the testing is quite comprehensive, and any comorbid disorders (ADHD, etc) would still be governed by the diagnosis of Autism. I think what is important is to pinpoint why the illness is causing aggression. For my son, it is usually stomach symptoms, which he is extremely sensitive to. It can also be environmental--too warm, too bright, he gets angry. Then you can teach your gd how to cope with these symptoms or let somebody know right away when she is feeling them, and learn how it affects her so she can control it. It took a while before my son realized, "when things are too bright, I get angry, so I will tell somebody to turn the light down or avoid bright areas."