What causes underarm darkening?

I hesitate to give someone a diagnosis without actually performing an examination.  I can think of several reasons for why someone's underarms would be dark, including a skin condition called acanthosis nigricans, hormone-associated hyperpigmentation, medication-related pigmentation and post-inflammatory... more

There are many causes for this such as: 1. excessive sweating 2. shaving with irritation, abrasion, hemosiderin deposition, etc 3. chemicals in antiperspirants such as the alcohols We recommend treatment for the underarm hyperhidrosis (Botox) or the other techniques, and perhaps laser hair removal to avoid the... more

Mechanical friction and skin irritation will make your underarm skin darker. Proper skin care, proper deoderant use, and in some cases hydroquinones, might help with this condition.