The incidence of
sudden hearing loss has increased. The pathogenetic mechanisms are still unknown, but
viral infections and vascular phenomena with acute impairment of microvascular perfusion are thought to play a major role. Infusion of hydroxyethyl
starch (HES) is used as a regimen to treat
sudden hearing loss. In our clinic,
anaphylactic reactions due to HES have not been observed so far. However, the use of HES is still discussed controversially due to long-term storage of HES molecules in tissue and due to high incidence of long-lasting
pruritus. In a retrospective analysis of 118 patients treated with HES for
sudden hearing loss, we observed
pruritus starting in 64% of patients one to three weeks after
therapy. This symptom with a duration between two weeks and four months was refractory to medical interventions. During
therapy with HES improvement of hearing was observed in 75% of patients, in 62% improvement of hearing persisted still at the end of the observation period (7 months post infusionem). Light and electron microscopic assessment of human skin biopsies of one patient
after treatment with HES showed storage of HES especially within dermal macrophages. Pathogenetically a pathway independent of histamin seems responsible for the induction of
pruritus. Accordingly, classic antihistaminic drugs had no
therapeutic effect in our patients.
Dextran is used as an alternative to hydroxyethyl
starch. In contrast to HES, the often mentioned higher incidence of severe
anaphylactic reactions due to
dextran has dramatically decreased with
hapten inhibition (after preinjection of monovalent haptendextran
Promit).(ABSTRACT TRUNCATED AT 250 WORDS)