Cats fur falling off from differant places!!!! Help!

This has been happening for a couple of week . She is having fur loss from differant part of fhe body! She is a spayed, 1 year 7 month old cat. Why is this happening? What could be the reason? Can the shampoo be the reason? When I brought her shampoo I didn't read the label. Now I feel may be the shampoo could be the reason, or could there be something else?
Here is the ingredients of the shampoo :
Sodium Lauryl Ether Sulphate,Cocamidopropyl Betain,
Quarternium -75, Cocamide DEA, Aloe Vera, D-panthenol, Sodium PCA, Silk Protein, Sodium Chloride, EDTA, Preservatives, Fragance, D&C color

Now that I read the label There are some bad ingredients. Could the shampoo be the reason? Or there could be other reasons? I actually don't find any other reason other than the shampoo. And Can you tell me what ingredients to aviod in cat shampoo? What are some of the best cat shampoos?

She had thick fur on her belly area, but now it looks like this ((
I will take her to the vet definately but want your feedback.

It could be the shampoo especially if it started happening right after. Is there a reason you needed to shampoo her? Most cats do not need to be washed regularly. If they do need it, water only is usually enough unless there's something really filthy or sticky.

It could also be allergies of some kind (fleas, food, environmental). Does she overgroom?

She never got very dirty,I bath her once every two or three month.
she does not overgroom herself, just normal grooming. She is the most gentle loving cat ever.

Btw she is an always indoor cat but she actually managed to get out of the house two weeks back and then returned that night.Could it be that she got somekind of allergy from going outside?

Anyone? Answer please.
Can you tell me what ingredients to aviod in cat shampoo? What are some of the best cat shampoos?

Why are you bathing her?  Cats generally don't need to be bathed unless you're showing them.  I have never bathed my cats except their paws when younger and were learning how to use the box.