alcohol does not affect allergy. you can be allergic to man made fibers. Using antihistamie tablets and applying antihistamine ointment can hep you.You may have to try different preparation. you may post your message in dermatology forum. you will get better suggestions as they are more expirienced.
Of course doing those things that you tried will make things much worse.
As much as it is itchy and hard not to scratch - Don't scratch! Easier said than done, I know.
Do NOT use any soaps, bath or shower gels.
Only wear cotton underpants. It makes no difference what the colour is as long as the fabric is cotton.
Use non biological washing detergents.
If you have not had a skin swab taken from your scrotum, then make an appointment to see your doctor and ask for a swab to be done to be sent to the laboratory to identify if there is any fungal or bacterial infections.
Best to wait for the results before trying any antifungal creams. But your doctor should be able to advise you and may prescribe something for you.
Hygiene is very important and you should wash in the morning and evening, using an emollient or plain water and gently dry. Wear clean cotton underpants every day.
If you are prescribed with antifungal creams or medications, you do need to use them as directed and it can take some time before you notice any change. Using a cream for a few days is not long enough to show any difference.
Your doctor can prescribe for you, or you can purchase from the pharmacy, without a prescription, an emollient to use instead of soap. This will moisturise the skin at the same time.
As a home remedy, after washing with water and gently drying the area, you can apply natural set yogurt to your scrotum or any where else that is itching. It will very cold. This will help to cool down the itching and help to reduce any inflammation in the skin. You can apply this as many times as you need to. There are no side effects doing this.
Virgin coconut oil may help, as this is not only moisturising to the skin, coconut oil has antibacterial and antifungal properties.
If you have diabetes, make sure you control your sugar levels.