Robert B. Rhoades

Survey of fatal anaphylactic reactions to imported fire ant stings

A physician questionnaire survey was conducted by the Fire Ant Subcommittee of the American Academy of Allergy and Immunology to document deaths caused by imported fire ant stings. From the 29,300 physicians surveyed, reports of 83 fatal and two near-fatal fire ant-sting reactions were received. Most anaphylactic deaths were reported from Florida (22) and Texas (19). After excluding duplicate reports, four confirmed deaths were documented in Alabama, 10 in Florida, two in Georgia, two in Louisiana, and 14 in Texas.

Treatment of perennial allergic rhinitis with cromolyn sodium. Double-blind study on 34 adult patients.

A double-blind crossover study was performed on 34 adult patients with perennial allergic rhinitis, using an aqueous solution of 4% cromolyn sodium or a placebo substance six times daily over a 4-wk period with daily documentation of both symptoms and use of symptomatic medications. All patients had markedly positive skin test reactions to at least one antigen. Chemistry screens and IgE serum levels were determined. Significant reductions occurred in the symptom-scores for runny nose, stuffy nose, sneezing, and nose blowing while patients were on cromolyn treatment (p less than 0.005). Likewise, while on treatment, there was a significant reduction in the consumption of antihistamines. In an attempt to differentiate between good and poor cromolyn responders by clinical and laboratory parameters, we found that (1) patients with high IgE levels responded better than those with low IgE levels, (2) patients with markedly positive skin test reactions to epidermoids and to foods responded better than those with pollen allergy, and (3) females appeared to have a significantly better drug response than males. Age did not play a role in drug response, nor did drug sequence (placebo-active or active-placebo).

Suppression of histamine-induced pruritus by three antihistaminic drugs

A double-blind crossover study of inhibition of histamine-induced pruritus by three commonly prescribed antihistamines was conducted on 28 normal subjects. Drugs used included diphenhydramine HCl (Benadryl), cyproheptadine (Periactin), hydroxyzine HCl (Atarax), and a lactose placebo in identical capsules. Intradermal histamine dose-response thresholds of pruritus were obtained before and after pretreatment with the three antihistamines and placebo in each subject. Analysis of data revealed a fivefold increase above baseline of the histamine dose required to produce pruritus following both cyproheptadine and placebo. This compared to a tenfold increase following diphenhydramine and a 750-fold increase following hydroxyzine HCl. The most common side effect was drowsiness, which occurred with all three drugs.

Hypersensitivity to the imported fire ant: A report of 49 cases

Two South American species of the fire ant group, Solenopsis richteri and Solenopsis invicta, now occupy more than 150 million acres in 13 southern states and cause systemic allergic reactions to their stings. We report 49 cases of such reactions with case reports and documentation. Specificity of the sting was documented by either typical pustule formation or positive skin tests. Of 37 patients treated with hyposensitizing injections, 10 have subsequently been restung. Only one suffered a systemic reaction. Problems of cross-reactivity with other insects are discussed and the literature is reviewed. Hypersensitivity to the imported fire ant continues to be a serious problem in the southern United States and appears to be amenable to properly instituted hyposensitization therapy.

Seasonal variation in antigens of the imported fire ant Solenopsis invicta

Eight sequentially collected lots of aqueous extracts of imported fire ant (IFA) front end and abdominal end segments were assayed for phospholipase A (PLA), N-acetyl-beta-glucosaminidase (NAG), and hyaluronidase. Relative potency of each extract lot and pooled venom was measured by RAST inhibition against a venom standard. More than a hundredfold difference in PLA activity was observed. Early summer collections had the highest activity. The May to June collection had more than twice the PLA activity of the next most potent lot. Discordancy in enzyme patterns was noted only in AE extract. NAG levels peaked earlier in the spring and summer and fluctuated less widely. Front end extract had lower activity levels for both enzymes, with no seasonal fluctuation in NAG and a single elevation in PLA activity in the April to May collection. RAST inhibition varied directly with PLA activity (p less than .05) but not with NAG nor hyaluronidase activities. Fifty-one percent of systemic allergic reactions to IFA stings occurred in summer, and 19% occurred in spring. A reported demographic survey demonstrated a higher incidence of IFA stings in the spring (39.9%) with a lower attack rate in the summer (31.9%). These findings suggest that the rate of systemic reactions to stings of the IFA may be related to seasonal variations in allergenic potency, as measured by PLA and RAST inhibition, rather than the sting attack rate.

Polysaccharide content of the poison apparatus of the cottonmouth moccasin Agkistrodon piscivorus piscivorus

Abstract The venom apparatus from decapitated adult cottonomouth moccasins was excised, sectioned, and stained by various histological and histochemical procedures. Biochemical analyses to characterize mucopolysaccharide extracted from the accessory and main portions of the glands were also performed. The accessory gland contains a mucosecretion which is a strongly acidic, sulfated, uronic-acid containing mucopolysaccharide.