exclamation point hair A short, broken-off hair that is found in an area of hair loss and is narrower closer to the scalp than at the other end (and therefore looks like an exclamation point). Exclamation point hair is a key diagnostic finding in a disorder called alopecia areata. See also alopecia areata.
excisional biopsy See biopsy, excisional.
excise To cut out entirely. For example, a scalpel or laser beam may be used to excise a tumor. The terms excise and resect are not synonymous. Excise implies total removal, whereas resect does not.
excess iron An overload of iron that can damage the heart, liver, gonads, and other organs. See also iron excess.
exanthem subitum A sudden rash. See also measles.
exanthem A rash on the outside of the body. By contrast, a rash on the inside of the body (for example, inside the mouth) is called enanthem. A patient with measles can have both exanthem and enanthem. See also enanthem; measles; rash.
exam, rectal See digital rectal exam.
exam, pelvic See pelvic exam.
exaggerated startle disease See hyperexplexia.
exacerbation A worsening. In medicine, exacerbation may refer to an increase in the severity of a disease or its signs and symptoms. For example, an exacerbation of asthma might occur as a serious effect of air pollution, leading to shortness of breath.
Ewing sarcoma See sarcoma, Ewing.
evolutionarily conserved sequence A base sequence in a DNA molecule (or an amino acid sequence in a protein) that has remained essentially unchanged throughout evolution.