- Almeida's disease (Brazilian blastomycosis) 116.1
- Alopecia (atrophicans) (pregnancy) (premature) (senile) 704.00
- Alpers' disease 330.8
- Alpha thalassemia 282.49
- Alpha-lipoproteinemia 272.4
- Alphos 696.1
- Alpine sickness 993.2
- Alport's syndrome (hereditary hematurianephropathy-deafness) 759.89
- Alteration (of), altered
- Alternaria (infection) 118
- Alternating - see condition
- Altitude, high (effects) - see Effect, adverse, high altitude
- Aluminosis (of lung) 503
- Alvarez syndrome (transient cerebral ischemia) 435.9
- Alveolar capillary block syndrome 516.3
- Alveolitis
- Alveolus, alveolar - see condition
- Alymphocytosis (pure) 279.2
- Alymphoplasia, thymic 279.2
- Alzheimer's
- Amastia (see also Absence, breast) 611.8
- Amaurosis (acquired) (congenital) (see also Blindness) 369.00