​Dermatology - Crust

​Dermatology - Crust 
The term "crust" originates from the Latin word for rind, bark, or shell.
 Crusts form when serum, blood, or purulent discharge dries on the surface of the skin.
• Crusts can vary in thickness and texture, ranging from thin, delicate, and crumbly to thick and firmly attached. Crusts can be felt by touch.
Crusts appear yellow when they are created from dried serum, green or yellow green when they are formed from purulent exudate, and brown, dark red, or black when they are formed from blood. Superficial crusts manifest as honey-colored, fragile, shiny particles on the surface. If the exudate covers the entire epidermis, the crusts can become thick and stick to the skin. If this is accompanied by tissue death in the deeper layers (such as the dermis), the disease is referred to as ecthyma.