- Jaccoud's nodular fibrositis, chronic (Jaccoud's syndrome) 714.4
- Jackson's
- Jacksonian
- Jacob's ulcer (M8090/3) - see Neoplasm, skin, malignant, by site
- Jacquet's dermatitis (diaper dermatitis) 691.0
- Jadassohn's
- Jadassohn-Lewandowski syndrome (pachyonychia congenita) 757.5
- Jadassohn-Pellizari's disease (anetoderma) 701.3
- Jadassohn-Tièche nevus (M8780/0) - see Neoplasm, skin, benign
- Jaffe-Lichtenstein (-Uehlinger) syndrome 252.01
- Jahnke's syndrome (encephalocutaneous angiomatosis) 759.6
- Jakob-Creutzfeldt disease (CJD) (syndrome) 046.19
- Jaksch (-Luzet) disease or syndrome (pseudoleukemia infantum) 285.8
- Jamaican
- Janet's disease (psychasthenia) 300.89
- Janiceps 759.4
- Jansky-Bielschowsky amaurotic familial idiocy 330.1
- Japanese
- Jaundice (yellow) 782.4
- Jaw - see condition
- Jaw-blinking 374.43
- Jaw-winking phenomenon or syndrome 742.8