Category: H

A severe and itchy inflammation of the skin occurring in people continuously subjected to the bites of the sandfly Phlebotomus papatasii. The incidence of this allergic skin reaction, prevalent in the Middle East, may be checked by controlling the numbers of sandflies.  

Any hooklike process, such as occurs on the hamate, lacrimal, and sphenoid bones and on the cochlea.  

Colored rings seen around lights by people with acute congestive glaucoma and sometimes by people with cataract. A coloured circle seen around a bright light in some eye conditions. When accompanied by headache, it is especially likely to be caused by glaucoma.  

A genus of hard ticks. Certain species transmit tick typhus in the Old World; H. spinigera transmits the virus causing Kyasanur Forest disease in India. A genus of ticks that includes species that are vectors for tick-borne viral diseases including hemorrhagic fever.  

An inherited abnormality of the proteins that normally stabilize the membranes of red blood cells. Hereditary spherocytosis is a common cause of hemolytic anemia among people of northern European descent; it is found infrequently among blacks and members of other ethnic groups. In some cases, the defect appears spontaneously, with neither parent affected by the…

Excessive or prolonged exposure to hydrogen sulfide, a highly toxic gas produced naturally by decaying organic matter. Hydrogen sulfide is sometimes called “sewer gas” or “stink damp.” It is a colorless, flammable, very toxic gas with a characteristic rotten egg odor. Hydrogen sulfide poisoning chiefly occurs through inhalation of the gas, although it can occur…

An abnormally low circulating blood volume. Blood loss in hypovolemia may be due to internal bleeding from the intestine or stomach; external bleeding from an injury; or loss of blood volume and body fluid associated with problems such as diarrhea, vomiting, dehydration, or burns. If the hypovolemia is severe, hypovolemic shock can occur, with symptoms…

Decreased muscle tone in infants, usually indicating the presence of genetic, muscle, or central nervous system disorders. Infants who are hypotonic feel floppy when held, and when at rest, they lie with their limbs loosely extended, unlike infants with normal muscle tone, who tend to flex their elbows and knees. Hypotonia, also referred to as…

A rare condition marked by the overstimulation of cells in the testicles in men and boys. It causes precocious sexual development and excessive growth. Hypergonadism causes early puberty in young boys. In men, symptoms may include male-pattern hair loss, excessive body hair growth, and acne. The resulting overgrowth of cells can produce enlarged muscles. When…

An antimalarial, anti-inflammatory drug. Hydroxychloroquine sulfate (Plaquenil Sulfate) interferes with the DNA protein synthesis of the microorganisms associated with malaria to prevent attacks of the disease. Because of its anti-inflammatory effects, hydroxychloroquine sulfate is also used to treat rheumatoid arthritis and lupus.