Perniosis is the appearance of sores from exposure to high temperatures.
A dermatologist is a doctor who specializes in diseases of the skin, hair, nails and mucous membranes.
The rheumatologist is the doctor who specializes in the diagnosis and treatment of diseases that affect the joints, muscles, tendons and bones.
A doctor or family doctor is responsible for diagnosing and prescribing medical treatments to patients. The family doctor refers to patients where a specialist when a specific treatment is required.
Remember that for the proper selection of health professional that treats perniosis you must consider the nature, severity and symptoms you are presenting.