Dermatology classifies lesions primarily by their visual appearance and texture. Lesions are divided into the general categories of primary and secondary. Primary lesions are those that are directly associated with the disease process and usually appear early in the course of the disease. Those appearing later are called secondary lesions and may be a result of the ongoing disease process and changes to the primary lesions.

A morphological classification of dermatological lesions is most helpful to the identification of the diseases present.

Primary lesions

• Macules
• Papules
• Plaques
• Nodules
• Vesicle
• Wheals
• Pustules
• Cysts
• Purpura

Secondary lesions

• Scale
• Crust
• Fissure
• Excoriation
• Lichenification
• Erosion
• Atrophy
• Ulcer