Your cold， defined<br >Here s a concise medical<br >description of a cold. " An<br >acute， usually afebrile， ca-<br >tarrhal respiratory tract<br >infection， with major in-<br >volvement in any or all air-<br >ways， including tile nose，<br >paranasal passages， throat.<br >larynx， and often the tra-<br >chea and bronchi." What<br >do these phrases mean?<br >Three major things: Colds<br >bring little or no fever ( afe-<br >brile)， cause increased mu-<br >cus flow (catarrhal)， and<br >may affect tissues from<br >your nose to your lungs<br >and anywhere in between.<br >Notice that a specific infec-<br >tious agent isn t mentioned.<br >A cold s symptoms are<br >distinctive but its causes<br >aren t， because the cause<br >can be any one of several<br >hundred viral strains<br >Medical Knowledge<br >about Colds<br > or centuries， people have suffered from the com-<br > mon cold， unable to point to its cause. Today，<br >specialists can describe with some precision what<br >causes colds. They ve made discoveries， too， about<br >how colds spread from person to person， who are the<br >likeliest targets， how colds can lead to more serious<br >illness. But specialists still can t tell you how to get<br >rid of a cold once you"ve caught it.<br >What is a cold?<br >The common cold is the most common illness suffered<br >by humans. If you don t have a cold right now， you re<br >almost sure to get one within the next 12 months.<br >Because we all have colds occasionally， we know what<br >we mean when we talk about this illness. If it weren t<br >for our common experience with colds， however， de-<br >fining colds would be next to impossible.<br > Colds are viral infections， but they re caused by<br >several hundred distinct viruses belonging to several<br >different viral families. To further complicate things，<br >your short bout with flu viruses or other viruses can<br >produce symptoms identical to those of more com-<br >mon cold viruses. Only when your symptoms pro-<br >gress in particular ways can anyone know whether<br >you have a cold or the flu.<br > Cold symptoms vary enormously. The usual symp-<br >toms include sneezing， sinus congestion， runny nose，<br >sore throat， cough， low fever， and headache. It you<br >experience any combination of these symptoms， you ll<br >probably believe you ve caught a cold. Of course， your<br >conclusion could be incorrect: the same symptoms<br > could signal the beginnings of another illness--<br > whooping cough， influenza， strep throat， or even an<br >Other names for a allergy. Sooner or later， if your symptoms worsen， if<br >cold they don t disappear when you think they should， or<br >Two terms describing colds<br >go back hundreds of years if uncoldlike symptoms show up， you 11 stop believing<br >Now seen mostly in medical you have a cold and start considering other diseases<br >books， catarrh and coryza Cold symptoms result from your body s defense<br >were once common ways of against infection. The inflammation that causes most<br >naming a runny nose. Both of a cold s symptoms is part of that defense process.<br >terms derive from Greek<br >roots meaning essentially Doctors think of a cold as a syndrome--a group of<br >the same thing， "increased symptoms that reach a certain severity and last a<br >flow." certain time. To say that you have a cold is， in a<br >Cold sym<br >What and<br >Runny， itchy eyes<br >Cough<br >Muscle ac~.~i<br >and pain<br >