Sorry to note your sister's symptoms.
has become a major problem with the growing urbanisation, changes in housing with little natural light or air and reliance on A/C units that increases the humidity.
Allergy testing is highly recommended to know the extent of her allergies, whether it is house dust mite, or mixed with animal dander, moulds, fungal spores, grass pollens etc.
There are various private labs in Mumbai that offer blood test
(would recommend specific IgE test rather than others) such as Metropolis etc and these need to be reviewed by an experienced Chest physician with interest in Allergy or an Allergist.
Long acting antihistamines such as allegra
180 oce daily, nasonex nasal spray
for 3 months is recommended. The tests will guide duration and seasonal therapy.
I hope this helps.