Dictionary

H. pylori Helicobacter pylori.

Haemophilus influenzae type B A bacterium that is capable of causing a range of diseases, including ear infections, soft tissue infection (cellulitis), arthritis, upper respiratory infections, and pneumonia; as well as such serious, invasive infections as meningitis with potential brain damage and epiglottitis with airway obstruction. Abbreviated HIB. HIB spreads by droplet through coughs and…

Haemophilus influenzae type B immunization An immunization designed to prevent diseases caused by Haemophilus influenzae type B (HIB). In the US, the HIB vaccine is usually given at 2, 4, and 6 months of age, with a final booster at 12 to 15 months of age. The HIB vaccine rarely causes severe reactions, and it…

hair, exclamation point See exclamation point hair.

hair, lanugal See lanugo.

hair follicle See follicle.

hairball A wad of swallowed hair. Hairballs sometimes cause blockage of the digestive system, especially at the exit of the stomach. Also called trichobezoar.

hairy cell leukemia See leukemia, hairy cell.

halitosis An unpleasant odor from the mouth, commonly referred to as bad breath. Halitosis can be caused by the consumption of certain foods, poor oral hygiene, alcohol or tobacco use, dry mouth, or by certain chronic medical conditions.

hallucinogen A drug or other chemical substance that causes hallucinations (profound distortions in a person’s perceptions of reality). Under the influence of hallucinogens, people see images, hear sounds, and feel sensations that seem real but do not exist. Some hallucinogens also produce rapid, intense emotional swings. An example of a hallucinogen is lysergic acid diethylamide…

hallux The big toe.

hallux valgus A condition in which the big toe (hallux) is bent outward (toward the midline of the foot; valgus) so that it overlaps the second toe. Hallux valgus may be accompanied by a bunion (localized painful swelling) and is frequently associated with inflammation. It can be related to inflammation of the nearby bursa (bursitis)…