Three reasons strong perfumes give you a headache

No two people will react to the same smell in the same way.
Humans can smell over 1 trillion odours. But no two people will react in quite the same way to the same smell. While there are some smells almost everyone agrees are unpleasant (such as paint thinner or rotten food), our reactions to other types of smells can be far more personal.
Take perfume. While one person may find the smell of a strong, floral perfume to be heavenly, another person may find it gives them a headache. There are many reasons why people can get a physical reaction to strong smells – but here are the three most common ones.
1. Emotions
Of all of our senses, only smell has a direct line to our emotional system. It’s thought the reason for this link is because smell evolved first of all of our senses. This means we don’t just perceive smell based on the odour chemicals presented to us, but together with all our memories of that smell – including the way it makes us feel, our past memories, and how we presently feel.
So let’s say you smell something you associate with a negative memory. Perhaps it’s the smell of cleaning chemicals used in a hospital, or the same perfume your ex used. One whiff may cause all those negative emotions to come rushing back to you, leading your body to generate a fight or flight stress response.
The fight or flight stress response is your body’s way of reacting to stress, anxiety or danger. It causes a number of physical changes, most of which are triggered by the brain going into high alert. One of the first changes you may notice during a fight or flight response is tension around the head and neck area. The reason for this is due to a vasodilation (widening of the blood vessels) which allows more blood to be diverted to the brain and parts of the body that need it.
Vasodilation also activates sensory receptors embedded in the blood vessels, which we perceive as headache pain if the blood vessels in the head and neck are the ones widening.
How we respond emotionally to certain smells is very personal, and based on a myriad of experiences. It may even be triggered by smells we may not even be conscious of smelling or consciously aware of our reaction to them. But if you tend to get headaches ...