4. Rash
If you develop a sudden rash, it’s almost always a sign that your body is trying to tell you about something else, and most crashes are caused either by a direct irritation to the skin – or by something that causes the immune system to respond from the inside with the creation of a rash on the skin.
If you are lactose intolerant, you’ll likely develop the rash a few minutes to half an hour from consuming any dairy or lactose-containing products – and you’ll also likely experience many of the other symptoms on this list together with it. Cut out dairy and lactose, and see if the rash goes away; it does, then you know that lactose was the cause of the rash in the first place.
If it doesn’t go away, make other lifestyle changes until there’s a change in the rash severity or it goes away by itself.