You are already doing a wonderful job managing her comfort with cetirizine (Zyrtec) and acetaminophen. To help her feel better, focus on keeping her hydrated with small, frequent sips of water, diluted juice, or warm broth. A cool-mist humidifier in her room and saline nasal drops can ease her congestion and soothe her throat. Offer soft, cool foods like yogurt or applesauce, but do not force her to eat. Since she has no fever, she is likely fighting off a mild cold. Keep offering comfort, and contact your pediatrician if her symptoms worsen.

Since your current routine of cetirizine (Zyrtec), montelukast (Singulair), and allergy shots isn't quite clearing it, you have a few safe options to discuss with your doctor. Using a saline sinus rinse daily can physically wash away stubborn mucus. Additionally, an expectorant like guaifenesin (the active ingredient in Tussin DM, which you tolerate) can help thin the mucus so it drains easier. Your doctor might also consider a prescription ipratropium bromide nasal spray, which specifically targets excess dripping. Please consult your physician to safely tailor these options to your needs.

You may take an over-the-counter antihistamine, such as cetirizine, once daily to help reduce itching. Applying calamine lotion or a gentle moisturiser to the affected areas can help soothe the skin and reduce irritation. If the itching is more severe at night and accompanied by small bumps, it may suggest scabies, in which case a doctor may advise applying permethrin cream from the neck to the toes, with a repeat after one week if needed. If symptoms persist or worsen, please consult a doctor for a proper diagnosis and treatment.

Moving to a colder, drier climate like Canada can sometimes trigger seborrheic dermatitis due to low humidity and indoor heating. It is completely safe to continue taking Zyrtec (cetirizine) and Becozyme C Forte (B-complex with Vitamin C) there. To help your scalp adjust, try using a humidifier indoors and a gentle, moisturizing shampoo.

Cetirizine (Zyrtec) has a wide safety margin. The sleepiness you are seeing is a normal, temporary side effect of the slightly higher dose and will wear off as the medication leaves her system. You should skip her next dose for today to let her body process the medicine. Keep her comfortable, monitor her breathing, and ensure she is waking up to feed. For peace of mind, please contact your pediatrician or local poison control center for a quick check-in.

Using cetirizine (Zyrtec) daily is generally safe for chronic hives, but diphenhydramine (Benadryl) can cause drowsiness and is best kept for short-term use. Since your hives have lasted over six weeks, they are considered chronic. While usually harmless, it is important to see an allergist or dermatologist. They can help identify potential triggers and prescribe safer, more effective daily treatments to give you lasting relief.