How do you explain this persistent red spot?

Case 1:

During a routine checkup, a 14-year-old girl inquires about a large red spot on her right ankle. The asymptomatic, erythematous area overlying the malleolus has been present for several months.

In-depth questioning of the patient revealed that she habitually curled her leg under her thigh when seated; this position caused both pressure and frictional irritation to the malleolus, D. A single affected spot ruled out psoriasis and dermatomyositis; the potassium hydroxide evaluation was negative for a dermatophyte infection. This patient was too young to have gout.

Reassurance and a suggested alternative sitting position were the only treatments necessary.