The evaluation of pilonidal abscess begins with a history and physical exam.

Physical findings in someone with a pilonidal abscess may include:

• Redness of the skin between the buttocks
• Tender lump under the skin between the buttocks
• Swollen lump under the skin between the buttocks
• Pus draining from the lump between the buttocks

Tests are not necessary to make the diagnosis of pilonidal abscess.

Tests that may be used to evaluate a pilonidal abscess include:

• Sinogram or fistulogram:
• Dye is placed in the cyst and then x-rays are taken
• Bacterial culture of pus
• Complete blood count