What should you know about Benadryl for fever?

Benadryl contains an antihistamine. It can reduce itching, sneezing, or a runny nose caused by histamine, but fever is a change in body temperature linked to infection, inflammation, or another illness. It may make someone sleepy and can hide how unwell they feel without addressing the cause. Combination cold products may also contain overlapping ingredients, so read every label.

Check the temperature with a suitable thermometer and encourage fluids, rest, and light clothing. For a child, use only a fever medicine and dose recommended for that child’s age and weight by a clinician or pharmacist; never use aspirin in children unless specifically directed. Do not give Benadryl simply to make a person sleep. A fever with cough, sore throat, rash, or breathing symptoms may occur with conditions such as Common Cold or COVID-19.

Seek urgent help for trouble breathing, a seizure, severe drowsiness, confusion, a stiff neck, a purple or rapidly spreading rash, or signs of dehydration such as very little urine. Arrange medical advice for a baby with a fever, a fever that is worsening, or a person with a weakened immune system. If fever follows travel or an animal or insect exposure, mention that history promptly.

What could be causing this fever, and how should I measure it? Which medicine is suitable for this person, given their age, weight, allergies, and other medicines? What warning signs should I watch for overnight?