Asthma, particularly severe asthma, is strongly associated with development of chronic obstructive pulmonary disease (COPD). Those with asthma, especially if it is poorly controlled, are at increased risk for radiocontrast reactions.Cavities occur more often in people with asthma. This may be related to the effect of beta 2 agonists decreasing saliva. These medications may also increase the risk of dental erosions. Causes
Asthma is caused by a combination of complex and incompletely understood environmental and genetic interactions. These influence both its severity and its responsiveness to treatment. It is believed that the recent increased rates of asthma are due to changing epigenetics (heritable factors other than those related to the DNA sequence) and a changing living environment. Asthma that starts before the age of 12 years old is more likely due to genetic influence, while onset after age 12 is more likely due to environmental influence. Environmental
Many environmental factors have been associated with asthmas development and exacerbation, including, allergens, air pollution, and other environmental chemicals. Smoking during pregnancy and after delivery is associated with a greater risk of asthma-like symptoms. Low air quality from environmental factors such as traffic pollution or high ozone levels has been associated with both asthma development and increased asthma severity. Over half of cases in children in the United States occur in areas when air quality is below the EPA standards. Low air quality is more common in low-income and minority communities.Exposure to indoor volatile organic compounds may be a trigger for asthma; formaldehyde exposure, for example, has a positive association.
Tick-borne diseases like Rocky Mountain spotted fever produce a rash that may become extensive enough so as to be classified as exanthemous in as many as 90% of children with the disease. See also
List of cutaneous conditions

References
External links

Overview at About.com
Definition at MedTerms
Differential diagnosis
Dermatology Quiz Includes photo, diagnosis, and treatment of unilateral laterothoracic exanthem (ULE).