Runner’s Itch?

This summer, I picked up on jogging, originally just for the fun of it. I have horrible endurance and I run out of breath quickly so the first few times were not so pleasant. But the more I jogged, the more I felt myself improve and I got a bit hooked on to going for a run after work. One fine evening, I went out for a quick run near a small lake and I noticed that my lower shin started to itch on both legs. I sat down by a bench and just couldn’t stop scratching it! I thought it must be some allergies from the plants. The itchiness was intense and persisted for a good few days before it subsided. It felt like mosquito bites all over my lower leg, but when I look at it, my legs look fine. No rashes, no abnormal spots, no redness. Just my skin.