Crepey Wrinkled Skin on the Inside of Arm

Crepey skin is just side effect of aging that has no real treatment.   It is due to genetics, weight loss, and sun damage.  Some people, when they lose subcutaneous fat with age, will develop crepey skin on their arms. This is not associated with massive weight loss, only the predictable loss of fat under the skin which starts in the fourth and fifth decades of life.  
To remove excess skin, a surgical brachioplasty is helpful.  However, the trade off of having a scar if you do not have tremendous excess skin may or may not be worth it for you.  If it's just a matter of the quality of the skin, topical treatments like mild chemical peels, lasers, and microneedling may allow for subtle improvement.   I also recommend that you keep your skin well-hydrated with good moisturizers. 

Excess skin of the upper arm or wrinkles can be removed and arms tightened with an arm tuck or brachiplasty that hides the scar under the arm.

In the case of a athletic thin woman such as yourself, the most likely reason for your wrinkled skin is natural aging processes in which the consistency and volume of fat below your skin changes, losing its support to the overlying skin and thus leading to wrinkles. Your skin also loses its elasticity with aging, sun damage and genetic influences, preventing the natural recoil to compensate for loss of subcutaneous fat. There are many non-invasive means to tighten the skin such as microneedling, radio-frequency skin treatments, skin peels, etc.  Depending on the amount and distribution of wrinkling, a formal arm lift (brachioplasty) may be best.  I would suggest consulting with a plastic surgeon for further guidance.  Thanks!

There are many reasons for crepey skin underneath the arms. This may be a function of aging, weight loss, natural skin tone, etc.   The treatment options for this type of skin range along the spectrum of plastic surgical care. Options include laser therapy, skin peels, radiofrequency tightening and surgical skin removal and tightening. The most definitive treatment is surgical intervention, but it does come at the cost of a scar, generally hidden on the inner portion of the arm/elbow. The results are generally very good and appreciated by the patients. It's critical that you seek the advice of a surgeon who is certified by the American Board of plastic surgery and has extensive experience in body contouring.I wish you the best, Dr. Gabbay. 

For crepey, wrinkled skin on the inside of the arms, the best solution is a modified arm lift with a short scar hidden on the inside of the arm.