Even though dark underarms is not a serious medical condition it may causes embarrass and low-self esteem especially if wearing tank-top or sleeveless shirt is what you like to do in summer.
What causes this condition, and who’s at risk?
The skin of your armpits is very delicate and can be irritated easily. The underarms skin folds over itself makes it more prone to hyperpigmentation
Friction is the most common cause of hyperpigmentation of skin. If you wear tightly fitted clothes, the fabric may causing irritation to your skin and in turn hyperpigmentation. Wearing comfortably fit clothes and choosing natural fabrics like cotton or silk over artificial ones lets your skin breathe and reduces the chances of irritation
2. Frequent shaving
Frequent shaving removes the protective top layer of your skin along with the hair. Thus the sensitive skin of your underarms is more exposed to sweat, dirt and skin care products, eventually leading to irritation and discoloration.
Strong chemical deodorants with alcohol and perfume may causing irritation and hyperpigmentation to your skin.
The bacteria that flourishes in your sweaty underarm not only causes the smell, but can also cause discoloration of your underarms.
5. Medical conditions
Although it is not very common, darker underarms might be signs of an underlying medical condition such as acanthosis nigricans, polycystic ovarian syndrome or Addison's disease, Obesity and hormonal disorders like insulin resistance/ diabetes or increase in serum cortisol levels can also cause darkening of the underarms.