The comparison distinguishes the tubotympanic or safe type from the atticoantral or unsafe type of CSOM.
Discharge and perforation
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Tubotympanic disease produces profuse, mucoid, odourless discharge and a central perforation.
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Atticoantral disease produces scanty, purulent, foul-smelling discharge and an attic or marginal perforation.
Local findings and complications
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Granulations are uncommon in tubotympanic disease and common in atticoantral disease.
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A polyp is pale in tubotympanic disease but red and fleshy in atticoantral disease.
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Cholesteatoma is absent and complications are rare in tubotympanic disease; cholesteatoma is present and complications are common in atticoantral disease.
Hearing
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Tubotympanic disease causes mild to moderate conductive deafness.
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Atticoantral disease may cause conductive or mixed deafness.