But real strep is by definition always a bacterial infection.
So I conclude that what the doctor is really sometimes is not "you have viral strep" but rather "you have a viral infection giving you a sore throat".
There is a home detector
This says strep throat only causes about 15% of all cases of sore throats with the vast majority caused by viruses
of cases of actual strep, in pre-adolescent children, the most common symptoms of strep throat are headache, abdominal pain and fever. Surprisingly, complaints of a sore throat, though customary in adolescents and adults, are habitually absent in younger children. The abdominal pain suffered by young children with strep throat can be so severe as to be mistaken for appendicitis.
Some strains of Group A strep produce a protein that causes the skin to become red and coarse. When this rash is present, especially when the child also has fever, it is called "scarlet fever". We know now that scarlet fever (also called scarlatina) is nothing more than (and no more dangerous than) strep throat with a strain that also causes the rash.
the only real test is a throad-culture, and the in-office (rapid antigen detection tests - RADT) culture has a higher false-negative (10-30%) than false-positive (5%) rate, compared to the gold-standard blood agar plate (BAP) culture grown overnight (typically sent out to a lab). So a quick-negative needs to be confirmed by sending it out, but a quick-positive is almost always right.
but this says Antibiotics have traditionally been used to cure strep throat and they are still recommended in the US. However, there is now controversy in Britain and in other countries about using antibiotics for a sore throat... Studies from the 1950s show that the use of antibiotics does reduce the rate of acute rheumatic fever following strep throat but this illness is rare... There is also concern that the infection can recur when strep throat has been treated with antibiotics... Antibiotics may be required for people who are seriously ill. They are also generally advised in parts of the world where rheumatic fever is common. They may also be recommended if there is also an accompanying Ear Infection with a sore throat.
- but given that it's infectious, doesn't it make sense to drug it so that you don't give it to someone else?
Group B Strep, or Streptococcus Agalactiae, can cause Perinatal Gbs Disease (an infection passed from the mother to child during birth). Approximately 10% to 30% of pregnant women are colonized with GBS in the vagina or rectum. Since the bacteria can come and go, testing for GBS is needed every pregnancy. Toward the end of a pregnancy, the vagina and rectum are cultured with a swab at a prenatal appointment. Women with GBS are given an antibiotic during labor. GBS is the most common cause of SepSis (infection of the bloodstream) and Mening Itis (infection of the lining and fluid surrounding the brain) and a common cause of Pneumon Ia in newborns. Group B strep bacteria are different from many other types of bacteria that can cause disease. People can be "colonized" with group B strep. This means that they carry the bacteria in their bodies but are not infected and do not become sick. Adults can carry the bacteria in the gastrointestinal tract, genital tract, or urinary tract. About 10% to 30% of pregnant women are colonized with group B strep in the genital tract. Colonization with group B strep is usually harmless. The bacteria can become deadly, though, if something happens that allows them to invade the bloodstream... Infection is fatal in about 20% of infected men and non-pregnant women and about 5% to 15% of infected newborns. Babies who survive can be left with speech, hearing, and vision problems as well as mental retardation... Since 1970, group B strep infection has become the leading bacterial infection causing illness and death in newborns in the United States. GBS is a bacterium that normally lives in the intestinal tracts of many healthy people. A vaginal-rectal area colonized by GBS should not be termed "infected" any more than an intestinal tract colonized by GBS would be. GBS is a problem only when it is present in the genital area of a pregnant woman during labor and delivery.