Given the many types of minor illnesses, the list of causes varies significantly, among the most common minor illnesses are caused by viruses or bacteria. Colds are caused by viruses and cannot be cured by antibiotics. You can, however, relieve the symptoms and support your body while it fights the virus. It is possible to get a sore throat from both viruses and bacteria, but these conditions are usually not serious. Inflammation in the throat causes dry coughs, while phlegm produced by the lungs causes chesty coughs. Phlegm that is extra thick leads to mucus cough, which requires thinning before coughing can take place. The body releases histamine in response to airborne allergens from pets, dust, and pollen entering the nose, resulting in headaches, runny eyes, constant sneezing, and an itchy nose. Pharmacy antihistamines block that histamine; consult the pharmacist before using, as they often have side effects.