Symptoms:
The underarms are discolored, or unusually darker than the rest of the body’s skin color. It may be accompanied by itching and bad odor caused by excessive sweating.

Causes:
Usage of commercially available deodorants will leave harsh chemicals to the skin. This is due to their ingredients that produce the smell or fragrances of the product.

Dead skin may build up in the underarm area due excessive sweating.

For obese people, friction cause by wearing tight clothes will irritate the skin.

Constant shaving irritates the skin and does not totally get rid of the hair below the surface of the skin.

Home Remedies:
Lemon: Slice a lemon fruit and use it to rub your underarms.

Alum: Use alum powder in replacement of deodorants.

Baking soda: Apply some baking soda to your underarms after taking a shower.

Vitamin E: Apply some deliberate amount of vitamin E in oil form to your underarm.

Coconut oil: Wash your underarms using coconut oil while doing your daily beauty regimen.

Lime: Mix 1 teaspoon of limejuice, 1 teaspoon of cucumber juice and a pinch of turmeric powder. Spread the paste mixture on the underarm area. Rinse well after 20 minutes.

Milk: Mix 1 tbsp. curd, 1 tsp. gram flour, a pinch of turmeric and 1 tsp. milk on your underarms. Apply the paste mixture on your underarms. Rinse with cold water when it dries.

Rose water: Wash the underarms area using a mixture of rose water and sandalwood powder

Other Treatments
Replace your anti-perspirant with an anti-fungal brand to get more effective results.

Wear cotton clothes as much as the occasion permits.

Regular waxing of the underarms will remove the dead skin and pull the hair out of their roots preventing its growth.