Brief Answer:
Please see the answer.

Detailed Answer:
Hi,thank you for posting your query on health care magic.

I have gone through your query and can understand your concern.

As per the information given by you,you are suffering from Perforation(hole) in the left ear drum.
It is frequently caused by nasal infection or any nasal pathology like Deviated nasal septum as they lead to Eustachian tube blockage.This is a tube which connects the middle ear with the nose and is responsible for equalization of middle ear pressure with the outer atmospheric pressure.
Blockage of this tube leads to negative middle ear pressure which may lead to fluid collection in the middle ear ,which may get infected with pus formation.This pus may drain outward causing hole in the ear drum.

On exposure to cold air as in AC,your nose may get blocked(oedema in the nasal lining) which may lead to Eustachian tube blockage and the resultant negative ear pressure may lead to infection in the ear causing pus discharge.

You need to have following examinations and tests before a decision of ear surgery is made:
1.Nasal examination by endoscopy by an ENT specialist Doctor-to find out any pathology for nasal obstruction like Deviated nasal Septum.If this is found to be significant,then the Nasal cause has to be corrected first(mostly by surgery) ,then ear surgery(Tympanoplasty) may be considered.
2.Examination of the ear has to be done by Autoscopy by an ENT specialist Doctor
to find out the Size of Ear drum hole.
3.Hearing test-Pure Tone Audiogram-needs to be done-to find out the degree of hearing loss.

If the hearing loss is more(moderate to severe) and there is repeated ear infection causing pus formation,then it would be advisable to go for an Ear Surgery called Tympanoplasty.
There are chances,that the hole in the ear drum may occur again in case of a nasal infection.But the chances are less ,it any nasal pathology like Deviated Nasal Septum ,is corrected first before ear surgery.

For the ear pus discharge,
You may take Antibiotic ear drops like Ciprofloxacin in the ear,
and an Antihistaminic-Decongestant oral medicine like Levocetrizine with Phenylephrine.
In case of severe ear pain,fever,etc,you may also need to start Oral Antibiotics.

For the care of ear :
Don't allow water to go inside ear while taking bath.
Don't try to clean your ear by self.
Avoid cold food and dust.

Hops this answers your question.I would be happy to answer if you have any follow-up questions.Take care.

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Brief Answer:
Take antibiotic drops

Detailed Answer:
Hi, thank you for your follow- up query.

Ideally, the ear surgery needs to be done only when the ear remains dry (without any discharge) for atleast 6 weeks.

You should take Antibiotic ear drops like Ciprofloxacin-for around 10 days and follow the lifestyle measures as advised previously.
If still the ear discharge remains, then you can have ear pus -to test for culture and Antibiotic sensitivity.It will help in identifying,that which organisms are causing the ear infection and to which antibiotics, they are sensitive. So that you can start Antibiotics, accordingly.
If you feel nasal blockage, you can even use nasal decongestant drops like Oxymetazoline , for a short while.
If possible ,try to avoid living in an AC,as it aggravates the pus formation from ear in your case.
If the ear remains dry,then there is no need of immediate operation.You may wait for a few months.

Hope this answers your question.Take care

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