Hello, 
Thanks for the  query to H.C.M. Forum. 
Swollen legs with mottled  red color. 
C O  P D, 
steroid . 
Since , how many days ,you are having this treatment ( steroid). 
The side effect of ( one ) steroid is retention of fluid on dependent parts ( legs). 
Other cause may be due to 
diabetes, 
May be due to renal disorders , 
You mentioned that she is taking treatment for 
high blood pressure , so when C O P D is there , may turn into congestive 
heart failure. 
Assessment for complete history is very important . 
Elevation of legs in chair is not a treatment , rather it is time being relief. 
Complete 
kidney function, heart function, liver function tests are required , if possible , upload the reports. 
Hope I  have answered your question. 
If further any question I will help. 
GOOD LUCK. 
Dr. HET