This is a medical question of type : information 
 What is (are) Problems with Smell ? 
 Our sense of smell helps us enjoy life. We delight in the aromas of our favorite foods or the fragrance of flowers. Our sense of smell also is a warning system, alerting us to danger signals such as a gas leak, spoiled food, or a fire. Any loss in our sense of smell can have a negative effect on our quality of life. It also can be a sign of more serious health problems. Aging and Smell Loss Problems with smell increase as people get older, and they are more common in men than women. In one study, nearly one-quarter of men ages 6069 had a smell disorder, while about 11 percent of women in that age range reported a problem. Many older people are not even aware that they have a problem with their sense of smell because the changes occur gradually over several years. They may not even notice that they are experiencing a loss of smell until there is an incident in which they don't detect food that has spoiled or the presence of dangerous smoke. How Our Sense of Smell Works The sense of smell, or olfaction, is part of our chemical sensing system, along with the sense of taste. Normal smell occurs when odors around us, like the fragrance of flowers or the smell of baking bread, stimulate the specialized sensory cells, called olfactory sensory cells. Olfactory sensory cells are located in a small patch of tissue high inside the nose. Odors reach the olfactory sensory cells in two pathways. The first pathway is by inhaling, or sniffing, through your nose. When people think about smell, they generally think of this pathway. The second pathway is less familiar. It is a channel that connects the roof of the throat region to the nose. When we chew our food, aromas are released that access olfactory sensory cells through this channel. If you are congested due to a head cold or sinus infection, this channel is blocked, which temporarily affects your ability to appreciate the flavors of food. Types of Smell Disorders People who experience smell disorders either have a decrease in their ability to smell or changes in the way they perceive odors. Total smell loss is relatively rare, but a decrease in the sense of smell occurs more often, especially in older adults. A decreased sense of smell may be temporary and treatable with medication. There are several types of smell disorders depending on how the sense of smell is affected. -  Some people have hyposmia, which occurs when their ability to detect certain odors is reduced.   - Other people can't detect odor at all, which is called anosmia.   - Sometimes a loss of smell can be accompanied by a change in the perception of odors. This type of smell disorder is called dysosmia. Familiar odors may become distorted, or an odor that usually smells pleasant instead smells foul.   - Still others may perceive a smell that isn't present at all, which is called phantosmia.   - Smell loss due to aging is called presbyosmia.  Some people have hyposmia, which occurs when their ability to detect certain odors is reduced. Other people can't detect odor at all, which is called anosmia.  Sometimes a loss of smell can be accompanied by a change in the perception of odors. This type of smell disorder is called dysosmia. Familiar odors may become distorted, or an odor that usually smells pleasant instead smells foul. Still others may perceive a smell that isn't present at all, which is called phantosmia.  Smell loss due to aging is called presbyosmia. Smell Loss May Signal Other Conditions Problems with our chemical senses may be a sign of other serious health conditions. A smell disorder can be an early sign of Parkinsons disease, Alzheimers disease, or multiple sclerosis. It can also be related to other medical conditions, such as obesity, diabetes, hypertension, and malnutrition. Getting a diagnosis early will help an individual deal better with the underlying condition or disease. Smell and Taste Smell and taste are closely linked in the brain, but are actually distinct sensory systems. True tastes are detected by taste buds on the tongue and the roof of the mouth, as well as in the throat region, and are limited to sweet, salty, sour, bitter, savory and perhaps a few other sensations. The loss of smell is much more common than the loss of taste, and many people mistakenly believe they have a problem with taste, when they are really experiencing a problem with their sense of smell. A loss in taste or smell is diagnosed by your doctor using special taste and smell tests. Smell Loss and Eating Habits When smell is impaired, people usually have problems appreciating the subtle flavors of food, and say that food is less enjoyable. Some people change their eating habits. Some may eat too little and lose weight while others may eat too much and gain weight. Either way, there may be a long-term impact on one's overall health. Loss of smell may also cause us to eat too much sugar or salt to make our food taste better. This can be a problem for people with certain medical conditions, such as diabetes or high blood pressure. In severe cases, loss of smell can lead to depression. Hazards of Smell Loss Research shows that people with a total or partial loss of smell are almost twice as likely as people with normal smell to have certain kinds of accidents. The most common types of accidents in order of frequency involve - cooking   - eating or drinking spoiled foods or toxic substances   - failing to detect gas leaks or fires  cooking eating or drinking spoiled foods or toxic substances failing to detect gas leaks or fires If you think you have a problem with your sense of smell, see your doctor.