This is a fairly standard logic grid puzzle, but there are fewer clues than normally seen. However, the clues are very constrictive, and the puzzle can be solved as normal. One possible logic path is as follows:
The third clue states that one three-day stretch was Stuffy Nose, Dylan, and Pecans, in that order. The fifth clue says that another two-day stretch consists of Shellfish and Milk, as well as Dizziness and Hives. Since the three-day period starts with a symptom and ends with an allergen, the two-day and three-day periods do not overlap, and must be one after the other, since there are only five days.
By the first clue, Sam had a reaction to either Shellfish or Soy, and the reaction was either a Stomachache or Stuffy Nose. Since Shellfish cannot have caused either of those, according to clue five, Sam is allergic to Soy.
Sam cannot be allergic to Shellfish, Milk, or Pecans, nor are they Dylan. By process of elimination, Soy gives Sam a Stuffy Nose. Knowing that, Dylan must be allergic to Eggs.
By clue four, the anaphylaxis occurred two days after Jordan’s reaction. Since Sam got the Stuffy Nose, the Pecans did not cause Anaphylaxis. This means that Eggs gave Dylan Anaphylaxis. More importantly, it means that Dylan’s reaction cannot have been on Tuesday, so the Shellfish allergy was on Monday, the Milk reaction was on Tuesday and it was Jordan, Sam’s Soy Stuffy Nose was on Wednesday, Dylan’s Egg Anaphylaxis was on Thursday, and the Pecan allergy was on Friday.
Combining this order with clue five, Hives were on Monday or Tuesday. From clue two, we know that Taylor must have had the reaction Monday, and Hives were Tuesday. Using clue five, this leaves Dizziness for Monday.
The last remaining person and symptom – Alex and Stomachache – must therefore end up on Friday.
The completed grid looks like this:
Read in order, the letters in the highlighted spaces spell out RENADEXTURALETTETRSINTHISTESXT. This looks close to a clue phrase, but it appears to have extra letters. Ignoring four of the letters, the phrase READ EXTRA LETTERS IN THIS TEXT. The extra letters spell out NUTS, the answer to the puzzle.