Pilonidal dimple

Alternative names:

sacral dimple, sacral sinus, pilonidal sinus

Definition:

A small pit or sinus in the sacral area just at the crease between the buttocks.

Considerations:

The majority of pilonidal dimples are harmless congenital anomalies that consist of a small depression or pit. These may be associated with increased hairiness around the area. The pilonidal dimple may also be a deep tract, rather than a shallow depression, leading to a sinus that may contain hair. These can become infected and drain. On rare occasion the tract (sinus) may extend into the spinal cord.

During adolescence the pilonidal dimple or tract may become infected forming a cyst-like structure called a pilonidal cyst. These may require surgical drainage or total excision to prevent reinfection.

Common causes:

• congenital pilonidal dimple
• congenital dermal sinus (of which the dimple is the mildest form)

Note: There may be other causes of a pilonidal dimple. This list is not all inclusive, and the causes are not presented in order of likelihood. The causes of this symptom can include unlikely diseases and medications. Furthermore, the causes may vary based on age and gender of the affected person, as well as on the specific characteristics of the symptom such as quality and associated complaints. Use the Symptom Analysis option to explore the possible explanations for a pilonidal dimple, occurring alone or in combination with other problems.

Update Date: 02/09/00
Updated by: J. Gordon Lambert, MD, Associate Medical Director, Utah Health Informatics and adam.com editorial