The cold weather of the winter season also brings more germs into the house. While most of these common cold germs go away with a tincture of time and a pinch of tender loving care, sometimes they progress into more than a cold and need medical treatment. Here's how to tell:

The common cold is usually caused by a virus and subsides within a week or so. However, it is important for parents to recognize when a cold is becoming more than a cold and needs medical treatment. The following guidelines will help you decide when to take your child to a doctor for treatment of a cold.

Determine how much the cold is bothering your child. If your child is happy and playful, eats well, sleeps well, and is not particularly bothered by the cold, then most likely it is a viral infection. The cold is simply a nuisance and probably will subside with the simple suggestions listed above. If, however, the cold is increasingly bothering your child, interfering with his sleep, play, appetite and general well-being, and it doesn't seem to be going away, it is wise to seek medical attention.

Check the mucus coming from your child's nose. If the secretions are clear and watery and your child is generally happy, the cold is most likely caused by a virus. If the discharge from the nose is becoming yellowish-green and thick and stays that way throughout the day, he probably has a bacterial infection, especially if he is becoming increasingly cranky and is awakening more at night. Nasal discharge usually appears yellow in the morning, after awakening, because of accumulations during the night. If the nasal secretions become clear during the day and your baby is happy, he probably has nothing more than a common cold.

The eyes are often a mirror of a cold's severity. Glassy, reddened eyes are often a clue that a child is ill. If your child has persistent yellow drainage from his eyes, he very likely has an underlying sinus or ear infection and should be examined by your doctor. In my office we strongly suggest that every child with a cold who has yellow drainage from the eyes come in for an examination. I have found that at least 50 percent of children with a combination of a cold and yellow drainage in the eyes will have an underlying ear and/or sinus infection -- more than just a common cold.

Antibiotics for colds? Viral infections generally do not need antibiotics, but bacterial infections do. When your doctor examines a child with a cold, he or she is trying to judge whether the infection is caused by a virus or by bacteria. Your doctor looks into your child's nose, throat and ears and listens to his chest in order to determine whether there are any signs of bacterial infection. Usually bacterial infections will cause sore-looking ears, thick, "snotty" drainage in the nose and throat, an inflamed throat, swollen glands under the jaws and noises in the chest. If none of these signs appear, your doctor may say to you, "This is a viral infection which does not need an antibiotic. Your child should get better by simply giving him plenty of fluids and cleaning out his nose. But call me if he gets worse."

Drown the cold. You've heard the expression "Starve a fever, feed a cold!" This bit of medical folklore is only half true. Best is to drown the fever and the cold with water. Fever makes you perspire and lose water, which dehydrates not only your body but also your brain, causing you to think and feel even worse from dehydration. During a cold, the mucus membranes of your nose and breathing passages lose water and dry out. Drinking water keeps these mucus membranes moist, which allows the inflamed lining of your nose and breathing passages to heal more quickly. Dehydration also thickens the mucus, making it difficult for the tiny hair filaments in your nose (called "cilia") to oscillate back and forth and move the mucus and the germs along. As a result, the mucus plugs collect in the nose, sinuses and airways and serve as a culture-medium for bacteria. Keeping the mucus and the membranes moist and waterlogged keeps mucous plugs from forming and even getting stuck in the lower airways, where they are difficult to cough up. In fact, among pediatricians, water has often been dubbed the "best and most readily-available cough syrup."

When is a cold contagious? A cold is most contagious in the very early stages, even before you notice cold symptoms. Usually, the longer the cold persists, the less contagious it is. As a general guide, the sicker the child, the more important it is to keep him away from other children. If a child has a clear runny nose and no fever and is not acting sick (he's just noisy, due to sniffles and coughing), it is usually unnecessary to quarantine him from other children. If, however, the child is coughing profusely, has a snotty nose and yellow drainage from the eyes, is running a fever, and is generally ill, consider him contagious and keep him away from other children for a few days. Colds are spread from droplet infection (through the air on the tiny particles coughed or sneezed from your child's respiratory tract), so it takes close contact to transmit a cold. I do not really believe that colds are easily transmitted by children handling each other's toy, but colds can be transmitted by germs on the hands. Encourage your child to keep his hands away from his nose and mouth. Frequent hand-washing can help prevent the spread of colds.

How to communicate with your doctor about your child's cold. Before phoning your doctor, have the following information available:

• Name and age of child
• When the cold began
• How the cold has progressed -- whether it is getting better, worse, or staying the same
• How much the cold is bothering your child's sleep, play, appetite
• The nature of the drainage -- clear and runny or thick, yellowish-green, and snotty
• The primary symptoms: fever, nasal discharge, eye drainage, cough, earache, etc.
• Symptoms have appeared only recently, as the cold has progressed: lethargy, paleness, pain in ears, around nose, in the throat
• Other symptoms: swollen glands, rash, persistent vomiting, drowsiness, difficulty walking, etc.
• How worried you are

ALWAYS check with your doctor if your child's cold is getting worse.

Echinacea for colds. While the jury is still out on whether or not echinacea can prevent colds, extensive studies from Germany have shown that it does stimulate the infection-fighting white blood cells and if taken at the very beginning of a cold can shorten the duration. There is no evidence that taking echinacea daily will prevent colds and, in fact, this practice has never been proven safe and should be discouraged. So when you or your child feel a cold coming on, take the appropriate dosage of echinacea: adults -- 300 mg., 3-4 times a day. The dosage for children has not been studied as much, but a sensible amount would be one-half the adult dose for children ages 6-13 and one-quarter of the adult dose for children under 6.

And don't forget grandmother's proven, time-tested and scientifically-correct cold remedies: get rest and plenty of extra fluids, blow nasal secretions out (don't sniff them in), "steamclean" nasal passages (using a vaporizer), avoid contact with respiratory irritants (such as cigarette smoke), zinc (zinc-fortified cereals), and feed your immune system with lots of vitamin C-containing fruits and vegetables.