Scleredema, formerly known as scleredema of Buschke, is characterized by tightness, thickening, and hardening of the skin, most often involving the upper back, neck, and shoulders. The dermis becomes thickened due to infiltration with hyaluronic acid. The face can be affected, leading to a "mask-like" facies with decreased oral aperture. Scleredema may also affect the heart, bones, joints, liver, spleen, eyes, bone marrow, salivary glands, nerve tissue, and tongue.

There are 3 clinical forms of scleredema:

• The classic type (type 1) is observed in patients after a recent bacterial or viral febrile infection and tends to resolve spontaneously over several weeks to months.
• Type 2 occurs without a preceding infection and follows a chronic progressive course. It can be associated with paraproteinemias (most often immunoglobulin G [IgG], followed by immunoglobulin A [IgA]).
• Type 3, also known as diabetic scleredema or scleredema diabeticorum, is associated with diabetes mellitus (DM) and is thought to be due to glycosylation of collagen. Unlike types 1 and 2, diabetic scleredema is observed more frequently in men.