asthma was first described by Hippocrates as a medical condition (at least those that we have a record of). So it must be around his lifetime, ~400BC.Subsequently asthma has been characterized by various people in various literature. See this entry from wikipedia:The word asthma is derived from the Greek aazein, meaning “sharp breath.” The word first appears in Homer's Iliad; Hippocrates
was the first to use it in reference to the medical condition.
Hippocrates thought that the spasms associated with asthma were more
likely to occur in tailors, anglers, and metalworkers. Six centuries
later, Galen wrote much about asthma, noting that it was caused by partial or complete bronchial obstruction. Moses Maimonides, an influential medieval rabbi, philosopher, and physician, wrote a treatise on asthma, describing its prevention, diagnosis, and treatment. In the 17th century, Bernardino Ramazzini noted a connection between asthma and organic dust. The use of bronchodilators started in 1901, but it was not until the 1960s that the inflammatory component of asthma was recognized, and anti-inflammatory medications were added to the regimen.