What is the reason behind night cough in my 7 year old daughter?

Check the foods which she is eating, based on that you can understand to which food she is allergic to.
Reduce on oil foods, ghee without heating, fresh grated coconut consumed directly may be a few reasons for cough.
My son used to get the same problem from drinking mango juice which we will buy from shops, tetra pack or bottled juice.
You could also add a pinch of salt, with hot water for lime juice prepared at home, sometimes this juice also could cause cough.
You can use a spoonful of honey with a pinch of pepper powder as an immediate medication to give some relief and make her sleep with high pillows sideways.

Since your daughter is hardly seven year old and hence care has to be taken that no excess allopathy medication has to be administered her to control the allergic problem. In fact, in the Allopathic- system, there is no effective cure of allergic disorders other than providing histamine which will arrest the issue for the time being.
You may undertake the following measures to take care of her allergies and this can be resolved with the herbs provided in the Ayurvedic- system without producing any side effects and treatment should be continued for at least three months with the given herbs-
1) Allow your daughter to take at least a tea - spoon of honey in the empty stomach both in the morning and evening and this being antibacterial, anti fungal and antivirus in nature will arrest her problem within a couple days say within ten days but this concoction is to be allowed for a month at least to have the permanent result.
2) Allergic problems are visible with the children having low immunity and hence ensure that her immunity is strengthened with the regular provision of half tea spoon of Giloy - powder of any reputed Ayurvedic- firm to be taken early in the morning along with some amount of hot water. Giloy alleviates tridosha of our body - system and hence its regular use for at least months will cure her permanently.
3) If the symptoms are acute in nature, allow her to take one tea - soon of Sitopaladi Churna of any reputed Ayurvedic Pharmaceutical along with honey for at least fifteen days. This will provide her immediate relief.
4) During night prior to retirement to bed, give her a glass of warm milk mixed with half tea - spoon of Haldi Powder. Regular consumption of such a concoction would give her permanent relief if administered for at least two months. It is due to the beneficial effect of Cur cumin present in the Haldi Powder.
5) Provide her warm water to be consumed in the regular way. It will enhance her metabolism.
6) Provide her Almond five to seven pieces in the morning ( soaked previous night with water), Walnuts in the moderate amount and Carrot - juice to boost her immunity in a natural way.

This cough in the night for a while may be due to an allergy only. The allergy may be due to the food she is consuming. Without knowing our body will develop an allergy towards certain foods. If we consume that food, it will give some side effects like that.
You have to see what are the foods she consumed on the day she had the cough problem and the food items she consumed on the day when there is no cough. This you have to study carefully for some days. Then you will understand which ingredient or ingredients in her food are causing this allergy. Then she should stop consuming those foods. Automatically the cough will come down. No necessity of consuming any medicines.
Meanwhile, you can ask her to take the following precautions.
1. In the night when she is starts coughing give her a glass of water and ask her to consume that water. Normally, cough will stop immediately.
2. Don't use any allopathic medicine for this cough.
3. A small quantity of black pepper can be boiled with water and filter the mixture and drink the solution. It will make cough to come down.

Coughing in children is not very uncommon. It is definitely a symptom of the underlying condition. There are many reasons why a child gets coughing in the night time but the relief is that many times it is not because of any serious reason. In such cases it is only a reflex of the body to keep the constrictions and mucous clear from the throat and chest. However a prolonged coughing condition necessitates to go to doctor for a thorough check up of the child.

There are different types of cough conditions that can manifest in a child but the most common is caused by the falling of mucous from the sinus and nose regions down to the throat and that thick and viscous cough clings there or sticks there to start the coughing process as the body would try to expel it out of that region to back in the mouth or nasal cavity. In an adult, one can manoeuvre it out and spit but a child is still small to do that type of action. This cough is basically created during the time when the child goes through an attack of cold and in the aftermath this problem of cough lingers on. This condition disturbs the child during sleep and he might even cry as a response to this sleep disturbance. These cough and cold conditions are generally triggered by the attack of various viruses on our body and they have some time period like 10-12 days after which they subdue in their actions and strengths as the body becomes much resistive to them through creation of antibodies and other body defence mechanisms.

We should not use the medicines generally available in the pharmacy shop as OTC medicines for curing of cough and cold in the children as they might affect the child due to their tender age. So, the better strategy would be to go to a doctor and then follow his advice. The doctor can give some cough syrup or drops for relief from congestion in the nasal cavity. The doctor would also check the child for any condition of Asthma in which such symptoms can arise.

You can give Ayurvedic syrups rather than allopathic syrups as allopathic are containing normally alcohol which affect the child well. If nothing available for you, you should have basil plant near to your house or Near Perumal /Narayan Temple - get some leaves put in a boiled water with two powdered pepper and filter. Give this filtered water to child after adding two or three drops of honey.

It seems your daughter is allergic to some food which you are including as the must diet for her during the dinner and probably she likes it and has the cough botheration after ward. Pepper is the great fighter of cough and if you can prepare pepper rasam for her during the night it would not only fight the sudden persisting cough and every child would eat the rasam rice for its great taste. And if you add some papad as the additional snack she would certainly eat the rasam with ease and there will not be cough problems. Keep always handy warm water at the be side so that any cough can be controlled with water intake as the first fighter.

This syrup is available in all patanjali stores. This can be taken by any age people and ayurvedic medicine only have no alcohol.

As your daughter is only seven years old. kids usually eat ice-creams, various candies and they catch an infection or allergy easily. Try to improve her immune system to increase the strength in her body to fight with cough etc.

Add Amla in her diet in any shape Amla Jam, Amla Juice, Amla Candy to improve immunity.
A small amount of Pure Ghee needs to be run on the backside of the palm under the tow between the first finger before going to bed on both hands.
Always drink clean water, avoid drinking cold water.