When I first got my parasites, I had hookworms (unbeknownst to me) and strongyloides, and they only caused problems in the summer. All winter, I was fine, like they were hibernating or something. Probably, they just went deeper into my body to stay warm, but in the summer...watch out! They headed to my skin and had a party!
But then again, you might just be extremely allergic to something in the ground where you live. Hookworm isn't that uncommon, especially where there are wild critters. Or it could be some type of fungus or bacteria. Allergies can make you very, very sick.