Might have brushed up against poison ivy.

"Certain parasites may be transferred from cat to human. Fleas are the most
common and cause itchy, sometimes inflamed, spots. Some people are more
prone to flea bites than others and some people react worse than others.
Ticks may also attach to humans but are picked up from long grass where a
gorged tick has fallen off of its former host; a tick attached to a cat
stays there until it is gorged or until it is removed by the
owner/veterinarian.
Some feline intestinal parasites can also be transmitted to humans.
Roundworm eggs infect humans, particularly children, through a faecal to
oral route. Tapeworm eggs are not directly infectious to people."
You might consider converting your "outdoor" cat to one of the indoor
variety for your own health reasons and also to prevent unnecessary
intrusion to neighbours who don't necessarily share your love of cats. Not
to mention the depletion of birds and small mammals.

Daz