My sister age 33, has suddenly noticed a honeycomb or spiderweb looking rash on her right thigh, also her left leg is slightly swollen mostly in the calf to ankle area. No swelling in the leg with the rash. The rash is not raised like hives, does not itch or burn. No pain other than periodic muscle cramp in left leg.
Hello, Welcome to Chat Doctor. From your description, the rash may be a pattern called as lived reticular. It is a pattern which could be associated with autoimmune disorders and antiphospholipid syn Chat Doctor.  This could also explain the painless swelling of the other leg. She requires a detailed evaluation for the same. However, a honeycomb rash on the thigh can also occur in a condition called erythema an Inge. This occurs after keeping a hot surface in contact with the skin for a long time (laptop, hot water bag, etc.). But this is not associated with limb swelling. Hope this helps you. Take care.