Dark underarms are not caused by any specific disorders and are not a sign of any harmful condition either. However, they are extremely unpleasant to look at and therefore a source of embarrassment, particularly if you have worn sleeveless clothes. Excessive perspiration, itchiness and an unpleasant body odor caused by sweat are the symptoms normally associated with dark underarms. Friction caused by the use of clothes, which are especially tight in the areas around the sleeves is considered to be the primary cause of dark underarms. This condition can also be caused due to excessive perspiration in the armpits or as a result of some skin infection or even due to an allergy brought on by a deodorant. In many cases women who prefer to shave their underarms, rather than get them waxed, are more likely to develop dark underarms. This occurs because the hair is not removed from the roots, and thereby leaves a dark shadow just under surface of the skin. There is also a possibility of in-growing hair. Dark underarms can also be caused due to the buildup of dead skin in the armpits.
If you are experiencing dark underarms, ensure that you wash them at least a couple of times daily and keep them dry and clean at all times. It is a good idea to refrain from using deodorants. Dusting some anti - fungal powder or even alum powder on your underarms would be very effective in keeping them dry. You can also opt to rub some baking powder on your underarms right after you have showered as this will help in reducing the perspiration which is one of the main causes of dark underarms. Studies have shown that vitamin E oil as well as coconut oil when applied to the underarms can be beneficial in lightening them considerably.
Wearing synthetic clothes, particularly during the summer, should be preferably avoided. It would be highly advisable for you to choose loose, cotton clothing, which does not create any friction against your underarms, thus enabling your skin the freedom to breathe. You can rub your underarms with some slices of lemon especially if they are excessively dark. Lemon has very powerful naturally occurring bleaching properties which can be used in lightening the skin of your underarms. An effective option is to prepare a paste using a teaspoon of freshly squeezed lemon juice mixed with a teaspoon of cucumber juice and a pinch of turmeric powder. Applying this paste over the affected area will help in reducing the darkening of the skin.
answered by G M