The cold days of winter bring most of us indoors for the year - and then the sniffles start up. Symptoms like sneezing, congestion, and sore throat are common during the winter months. These unpleasant symptoms can be evidence of a winter cold, but they can also mean indoor allergies. What are the causes of these winter ailments, and how can they be identified (and treated)?

Winter weather can indirectly cause both colds and indoor allergies. Colds increase in winter because people spend more time inside, confined to small spaces where viruses and germs can be easily passed around. Also, the viruses which cause colds thrive in low-humidity environments, which are typically found in the cold dry months of winter. Low humidity, combined with air blowing from indoor heating systems, causes drying of the nasal passages, which can increase susceptibility to infection.

With indoor allergies, it's a similar story. Indoor allergies are caused by dust, which contains a wide variety of allergy-causing particles like animal dander, mold spores, pollen, dust mites and dust mite waste. Spending more time indoors means increased exposure to these allergens. Plus, indoor heating systems circulate air through the house, knocking loose many allergy causing particles on carpets, furniture, and dusty shelves. Then, these allergens are circulated through your home, right along with the warm cozy air.

Colds and allergies also show themselves in very similar ways, making it difficult to tell them apart. Symptoms of colds include congestion, stuffy nose, swelling of sinuses, sneezing, scratchy sore throat, headaches, aches and pains, fever, and a cough. Allergy symptoms include stuffed or runny nose, sneezing, wheezing, sore throat, watery and itchy eyes, and sometimes headaches. The main difference between cold and allergy symptoms is that colds usually come with body aches and pains and possibly a low-grade fever, while allergies do not. In addition, colds usually last 7-10 days, while allergies will persist as long as the exposure to the offending allergen continues. If you have cold-like symptoms which persist for more than two weeks, it's a good guess that you're dealing with an allergy, not a cold.

Complicating matters, frequent colds may in fact result from allergies. Your body responds to tiny allergens by producing mucus, in an attempt to expel them. However, nasal mucus is also a breeding ground for viruses and bacteria, which can cause colds and sinus infections. Treating allergies will help prevent these, which is why it's a good idea to identify allergies early and treat them accordingly.

It's important to distinguish between colds and allergies, in order to give appropriate treatment. Cold viruses thrive in low humidity, and nasal dryness can lead to increased susceptibility to colds, so running a humidifier in cold dry winter months may be helpful. However, dust mites thrive on high humidity, so if you're suffering from indoor allergies, the low humidity is your ally. And while rest and plenty of fluids may cure a cold, allergies will persist as long as exposure continues.

To treat and prevent indoor allergies:

• Visit an allergy doctor who can help you identify the offending indoor allergens
• Maintain low indoor humidity to kill dust mites and mold
• Vacuum using a HEPA filtered vacuum and run a HEPA air purifier to remove airborne allergens
• Encase mattress, pillows, and bedding in allergen-barrier encasings to protect from dust mite allergies
• Dust and clean frequently

To treat and prevent winter colds:

• Wash your hands frequently and disinfect surfaces
• Get plenty of exercise and rest
• Eat nutritiously, with lots of fruits and vegetables
• Avoid alcohol, tobacco, and excess stress
• Relieve cold symptoms with nasal decongestants and cough suppressants

When treating a cold, remember that medicines may relieve symptoms, but they will not cure the cold. Only giving your body the proper care it needs - rest, proper nutrition, and plenty of fluids - will cure the cold. And with allergies, the best way to treat allergy symptoms is to remove the offending allergens from the environment.