We describe a type 2 diabetic patient who showed immediate-type
allergy against human
insulin associated with marked
eosinophilia at initial
insulin therapy. Three months after initiation of
insulin therapy, he noticed itchy skin wheals at the site of the
insulin injection. Laboratory data at that time showed marked
eosinophilia (2,512 /mm3) and progression of renal dysfunction. Skin test with semisynthetic human
insulin and
protamine sulfate resulted in local immediate skin reactions such as itchy
erythema and wheals. Histopathology of the biopsy specimen from skin showed perivascular infiltration of lymphocytes and numerous eosinophils in the dermis and subcutaneous fat. Although the titer of total
IgE antibody was within normal range, that of
insulin-specific
IgE antibody was high.
Insulin administration was discontinued to preserve his insulin secretion, and stable control of his
hyperglycemia was obtained by initiating
nateglinide treatment (360 mg/day). His itchy skin lesions disappeared within two weeks after cessation of the
insulin therapy and both
eosinophilia and renal dysfunction gradually improved. Although the widespread use of human
insulin in diabetic patients has greatly reduced the incidence of
insulin allergy, the possibility of human
insulin allergy should be kept in mind when initiating such
therapy.