Many different things can trigger a hot flash. Emotional triggers, such as embarrassment, are among the most common. Other hormonal issues can also be triggers for hot flashes. For example, if you take too much thyroid hormone for hypothyroidism, you may have a hot flash. Elevated cortisol levels due to stress can also lead to hot flashes. Other potential triggers include fluctuating blood sugar levels, any kind of adrenaline surge, alcohol and foods that contain MSG.