Asthma is a very common condition and a little less than 10 percent of the global population is believed to suffer from this disease . Patients will undoubtedly have distress when they encounter a flare-up of asthma but it is a disease that can be well-controlled with medications so flare-ups should be rare. Treatment of asthma is relatively straightforward once a diagnosis is made but it can be a challenge to make the initial diagnosis. A chest X-ray may be the first step in the initial diagnosis and when suspicious densities on your lungs are seen, this may not be one of the obvious signs of asthma that doctors will look for. It may take some time in order to finally get to the bottom of what is occurring to you.
What is Asthma?
As I already have eluded to, asthma is a very common disease that can present in both young children and adults for the first time. You do not have to have a long history from childhood in order to still be susceptible to have asthma later on in life. It is a chronic lung disease that is associated with the narrowing of the respiratory airways. This narrowing can cause severe dyspnea, chest tightness, coughing and wheezing. The coughing may be worse early in the morning or at night.  Studies in medicine have shown that you can be at risk for asthma if you have a family history of the disease as well as living in a highly polluted environment. Large urban areas with poor air circulation are areas where children are most likely to have the disease. 
The treatment for this disease is dependent on medications that can quickly and effectively help open up the airways to allow the patients to breath better. The most common medications are a combination of inhaled steroids and long-lasting beta-blockers . The more frequent a patient experiences flare-ups of asthma, the more aggressive the treatment needs to be in order to help reduce these periods . There are easy-to-understand medical charts that your pulmonologist and maybe even your family doctor will surely have in their offices to help explain this chart in more detail but the take-home message you should be aware of is that you should not have more than one or two flare-ups per month. If you find yourself with more frequent attacks, you need to go to your doctor and strengthen the dosages of the medications you are taking. The proper treatment will be successful in most cases. 
How Will it Present on a Chest X-ray?
It is not an easy diagnosis to make when you are trying to decide if a patient may have asthma. Spirometry studies will need to be done in order to determine how a patient is able to breathe in certain circumstances. When abnormalities are present, this essentially confirms a diagnosis of asthma but chest X-rays are sometimes necessary to assess the severity of the disease. In one study done to determine if there is a true value in having a chest X-ray in the diagnosis of asthma, 58 patients already diagnosed with mild to moderate asthma were analyzed to determine what diagnostic test was ultimately successful at making the final diagnosis. In this study, only 21 of 58 patients (roughly 36 percent) were diagnosed with asthma after having abnormal spirometry studies. When it comes to a chest x-ray, however, 34 of 58 patients were found to have increased markings or lower diaphragms; two indications of an asthma infection.  Consider these markings to be suspicious densities on your lungs that doctors will need to further investigate.
As you can see, both of these commonly used studies may not be able to clinch a diagnosis of asthma after one simple test and most of the time, asthma will be without any obvious signs on a chest X-ray. Why a chest X-ray is necessary for these patients though is because there are numerous diseases and syndromes that can have a presentation similar to asthma. Ingesting foreign bodies accidentally, especially when considering young children, or pneumonia can present with difficulty breathing and wheezing. An X-ray can exclude these possibilities in order to help pinpoint the focus more on asthma.
One of the other signs of asthma that was discovered was that asthmatic patients may also have physiological changes to their anatomy that can be evident on a chest X-ray. In one investigation, it was seen that when 57 patients with asthma were compared against 57 patients without asthma, the angle of the rib cage tends to be less sloped than in patients without asthma. This slope indicates that your lung cavities will be smaller and it can be harder for patients to breathe when there is a reduction of pressure in the space during an asthma attack.