Sand flea bites can show up days later due to delayed reactions to the flea’s saliva. The bites may initially go unnoticed and then develop into red, itchy welts.

Sand flea bites may not cause an immediate reaction, leading to delayed itching and swelling. The body’s allergic response to the flea’s saliva is what triggers the visible symptoms, and this can vary from person to person. Applying anti-itch creams and avoiding scratching can help manage the irritation. In some cases, the bites may take several days to fully heal.