Do mosquitoes make a beeline for you and ignore your companion?
You are not crazy. Ticks do like you.
A recent European study showed a species of Ixodes ticks preferentially seek out certain blood types. From the ABO Rh subgroups ticks prefer type O blood and type B blood is relatively protective. Ticks find type A blood only slightly less appealing. Ticks, mosquitoes and other blood sucking insects are primarily attracted by CO2 but there are other important factors. The insects can detect hundreds of volatile organic compounds which emit signature scents from our skin. Sweat plays a role. Skin flora play a role. Other genetic factors may be in play.
I am lucky and have type B blood – 9% of the US population. You are probably not so lucky.
It is true: some of us smell sweeter to ticks and mosquitoes than others of us.
Certain chemicals make us less attractive. DEET and Picardin are well known insect repellents and are moderately effective. Other natural substances may be effective, such as: lemongrass, citronella, cedar, peppermint, lavender and geranium.
I have no specific recommendation here. There is a lot of discussion on the internet. A patient recently told me he combines several of these substances and has good results.
The most important preventative is permethrin. Permethrin is applied to clothes and allowed to dry overnight. Clothes pretreated with permethrin are commercially available. Permethrin persists in/on fabric for a month or more – even if clothes are washed.