What does keratosis mean?
Keratosis is a medical term for an abnormal buildup of keratin, the tough structural protein normally found in skin, hair, and nails. It commonly describes a rough, thickened, scaly, or crusty lesion, including actinic keratosis, which is associated with long-term sun exposure, and seborrhoeic keratosis, a common benign growth in older adults. The word can also refer to keratinizing abnormalities in tissues such as the mouth or vocal folds. Although many keratoses are harmless, medical evaluation may be appropriate when a new lesion changes, bleeds, becomes painful, or persists, because some forms can be associated with precancerous changes. In general usage, keratosis is mainly a clinical term rather than an everyday expression.
nounA condition characterized by the abnormal buildup of keratin in the skin, often forming a rough, thickened, scaly, or crusty lesion. The term is also used more broadly for similar noncancerous growths in other tissues.
- A thickened, scaly, or crusty growth caused by the abnormal accumulation of keratin in the skin.
- A noncancerous keratinizing growth in another tissue, especially the mouth, tongue, or vocal folds.
"The dermatologist recommended treatment for a small actinic keratosis on her forehead."
"His doctor monitored a seborrhoeic keratosis rather than removing it immediately."
"The biopsy showed oral keratosis with no evidence of cancer."
The standard plural is keratoses, with the final -s pronounced /siːz/.
"Several actinic keratoses were found on the patient's sun-exposed skin."
Actinic keratosis is a warning sign of cumulative sun damage, so a small rough patch can matter more than it looks.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Where does keratosis come from?
The word comes from Greek keras, meaning “horn,” combined with the suffix -osis, indicating a condition. Its development reflects the historical association between thickened keratin and horn-like growths. Modern medical derivatives such as keratin, keratocyte, and keratopathy continue to use the same Greek root.
Related word forms
How keratosis is actually used
This is primarily a medical term. In ordinary clinical usage it most often refers to a skin lesion, and the specific type should be stated when it matters; for example, actinic keratosis is associated with sun exposure, while seborrhoeic keratosis is a benign, age-related growth.