This rash could certainly be related to seasonal allergies. The most common symptoms of seasonal allergies are actually runny nose, congestion, sneezing, and itching eyes. However, in some people, there is also a skin rash. I would probably call this rash eczema
, which is sort of the allergic skin equivalent of what happens in the nose and eyes with the more typical presentation of seasonal allergies.
Eczema can fortunately be easily treated in most cases. The mainstay of eczema treatment is good skin moisturizing. I prefer a thick, greasy moisturizer like hydrolated petrolatum, which traps in the skin's natural oils and prevents drying out better than standard lotions and creams. It should be applied multiple times per day, especially after showering or bathing. You should also avoid very hot water and harsh soaps, as these will make the eczema worse.
You can try applying an over the counter topical steroid, such as hydrocortisone, which should help with the redness, itching, and inflammation. Avoid scratching at all costs, as this will make you run the risk of getting infected areas.
Sometimes stronger medicines are needed to get the rash under control, so I also recommend discussing this with your primary care doctor