They strike toward the warmest spot, which is the head, she strikes whenever you handle her because she is either stressed (husbandry not meeting her needs or over handling) or not being fed enough, they do not all react the same way even if they are kept in the same manner or handled the same amount of time, some are more subject to stress than others.
How big is she (weight?) and how big is her enclosure? How often do you handle her?