2.2 Crust

Crust

Surface deposits of dried secretions (serum, pus or blood), usually mixed with epithelial and sometimes bacterial debris
Color: yellow (serum, pus), brown-black (blood)
Size: several mm to cm

May appear anywhere on body, usually localized.

May develop into erosion or ulcer
Associated with vesicle or pustule
When crusts become detached, the base may be dry or red and moist

All diagnoses associated with exudation of fluids.

Exudation of serum; leakage of blood following trauma, lesion type following papule, pustule, plaque, vesicle and bulla