This may be due to skin irritation caused by constant friction that occurs in the area. The thighs may rub together while waking or during certain exercises and the abdomen is exposed to clothes and pants.The cloths of which may rub and indent the skin.
The area also are usually covered and may be damp and moist at most times, this may encourage growth and colonization of skin bacteria which may cause the skin condition. Folliculitis may be another differential here. A sweat rash may also be considered.
Try to keep the area dry and clean at all times. Try wearing loose clothes of light material. You may opt to place a light vitamin E cream in between the thighs to avoid constant friction.
Try to observe if the condition improves. Watch out for any involvement of other parts of the body like the face and the scalp.
It's only really on the front of my thighs not really in between. When I first noticed it though was after playing basketball and sweating. So I have been keeping it dry. The last few days also it has moved to the back of my thighs and knees also.
This may be a case of a contact dermatitis or a fungal infection. A sweat rash may also be considered here. A sweat rash may be associated with sun exposure for instance and may present with a red rash. A dermatitis may be due to an unknown trigger. The cloth may be a factor here.
Continue to keep the area dry. Do not allow your clothes to dry on your skin. Wash after strenuous activities and change into fresh clothes as soon as possible. If the rash persists and if pain or other changes in color and size are noted then seek immediate consult.
Corticosteroids may help. Do not self medicate however, as steroids do have their side effects.If there is any way you can find a primary physician to guide you through this.Using inappropriate medication may only worsen the condition.