My son has had an allergy since yesterday. I gave him Benadryl® and this morning dexchlorpheniramine, but he isn't improving. I gave him the latter about an hour ago. Can I give him cetirizine?

Hello, Daniel: I understand your concern, especially when it involves a child. In general, I do not recommend combining several antihistamines without medical indication, as increasing the dose or switching from one to another within a few hours does not usually provide additional benefit and can increase the risk of side effects, such as excessive drowsiness or irritability. The most important thing is to identify the cause of the allergic reaction and assess whether it really is an allergy or another skin or infectious problem. If the child only has itching or a mild rash and does not improve with treatment, the most sensible thing is for him to be assessed by his paediatrician to adjust the medication. On the other hand, if difficulty breathing, swelling of the lips or tongue, hoarseness, repeated vomiting or significant listlessness appear, you should go to an emergency department immediately. I hope your son recovers very soon. Kind regards.