downgrading reaction
a type 1 lepra reaction, similar in appearance to the reversal reaction (upgrading reaction), but representing a deterioration in the immune response to Mycobacterium leprae, worsening of clinical symptoms, and an increased index of M. leprae in the tissues. It may be seen during antileprosy treatment if the strain of M. leprae has become drug resistant or the patient has had poor compliance with the drug regimen.
Medical dictionary.
2011.