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Keywords:

  • IgE-mediated anaphylaxis;
  • latex allergy;
  • rush immunotherapy;
  • sublingual immunotherapy;
  • systemic hypersensitivity reaction

Not many studies have reported clinical experiences on effectiveness and safety of sublingual (swallowed) immunotherapy (SLIT) in patients with allergic, IgE-mediated reactions to latex (1, 2). In the studies quoted the scheduled SLIT (Table 1) includes a starting rush phase in 4 days, reaching the dose of 25 drops of the highest concentration. The same scheme is used in our allergy section, as proposed by the producer.

Table 1.   Treatment schedule of latex sublingual immunotherapy
DayVialDose (drops)Concentration (μg/ml)Interval (between doses)
Rush phase
10 15 × 10−815 min
1015 min
1 15 × 10−515 min
10 
22 15 × 10−215 min
1015 min
3 1515 min
10  
34 150015 min
 2 15 min
 3 15 min
 4 15 min
10  
4425  
Maintenance phase
64 5 2 days

The latex extract we employ (Alk-Abello’, Milan, Italy) is an ammoniacal extract quite similar to the one used in manufacturing latex gloves and other articles. So, it contains the major allergen Hev b 5, which is not found in the natural extract. The extract is standardized in w/v and, at his highest concentration, it contains 500 μg of proteins per millilitre.

The present communication concerns a 36-year-old woman with latex allergy, affected by urticaria and asthma challenged by the handling or the exposition to latex articles and treated with SLIT. About 20 min after the maximum scheduled dose, the patient showed cutaneous rash and spreading urticaria followed at once by an asthma attack and a serious condition of anaphylactic shock with required treatment in emergency room. The reported case suggests the following remarks.

Evidence based studies demonstrate that subcutaneous allergen-specific immunotherapy (SIT) is effective for the treatment of allergic respiratory diseases. However systemic reactions, sometimes severe can occur during SIT including occasional fatalities. For these reasons new vaccine with modified-allergens (s.c. allergoides) and a number of alternative methods of immunotherapy have been tried.

Among the latter, SLIT proved effective and safe without the risk of severe systemic reactions observed with SIT (3). The high safety of the method allowed home administration. An analysis of published studies yielded the surprising result that SLIT with high doses is safer than SLIT with lower usual doses (4). In other words, it seems there is no correlation between doses increase and increased risk of adverse reactions. For this reason most allergists deem that rush SLIT can be practised without hazards, leading within days to a reduction of symptoms (5).

These statements can be regarded as true in almost all cases, but exceptions to the rule exist. Uncommon cases of systemic reactions, sometime severe, have been observed during SLIT (6). The case here reported confirms that rare possibility.

It is possible that, because of its excellent tolerability, benefits from rush SLIT largely overcome possible risks. The case we report is an anecdotic one. As for latex allergy, in spite of the previously quoted studies and waiting for the results of the other ones, we should consider that the rush phase of SLIT to latex is loaded a priori, as the rush SIT is, by higher risk of adverse events. In our opinion rush phase of SLIT to latex should always be performed in protected setting, where emergency treatment and intensive care room access must be available.

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