Malignant idiopathic anaphylaxis

Idiopathic Anaphylaxis: a Perplexing Diagnostic Challenge for Allergists

PURPOSE OF REVIEW

The aim of this systematic review is to present the proposed theories of pathogenesis for idiopathic anaphylaxis (IA), to discuss its classification, its diagnostic approach, and management.

RECENT FINDINGS

IA represents a major diagnostic challenge and is diagnosed when excluding the possible identifiable triggers of anaphylaxis. The current research, however, revealed that certain conditions including mastocytosis, mast cell activation syndromes, and hereditary alpha tryptasemia can masquerade and overlap with its symptomatology. Also, newly identified galactose-alpha-1,3-galactose mammalian red meat allergy has recently been recognized as underlying cause of anaphylaxis in some cases that were previously considered as IA. IA comprises a heterogenous group of conditions where, in some cases, inherently dysfunctional mast cells play a role in pathogenesis. The standard trigger avoidance strategies are ineffective, and episodes are unpredictable. Therefore, prompt recognition and treatment as well as prophylaxis are critical. The patients should always carry an epinephrine autoinjector.

Pediatric idiopathic anaphylaxis: experience with 22 patients

Idiopathic anaphylaxis in the pediatric population is being increasingly recognized, with symptoms (and therefore classifications) the same as those described in adults. We present a series of 22 patients with special attention to considerations relatively unique to the pediatric population. Prednisone, hydroxyzine, and albuterol were used to control symptoms and induce remission. No deaths occurred during treatment. One adolescent who presented with corticosteroid-dependent idiopathic anaphylaxis was diagnosed with undifferentiated somatoform-idiopathic anaphylaxis. Local physician reluctance to participate in management complicated care for some patients.

Idiopathic anaphylaxis: a series of 335 cases

BACKGROUND

Idiopathic anaphylaxis is anaphylaxis with no definable etiology and no trigger by exogenous allergens. Initially described in 1978, idiopathic anaphylaxis has been subsequently characterized and treatment protocols have been established.

OBJECTIVE

The demographics and course of 335 patients (225 previously reported) treated with prednisone, hydroxyzine, and albuterol are now reported.

RESULTS

Ages ranged from 5 to 83 years. There were nine new pediatric patients in this series totaling 14 (4.2%). Atopy was common (48%) with 34 new patients with asthma. The duration of symptoms prior to presentation ranged from three days to 27 years. One hundred thirty-two patients with idiopathic anaphylaxis were available for follow-up. Twenty of these are currently receiving prednisone for control of idiopathic anaphylaxis, seven of them as part of their initial therapy, and ten for control of recurrence of symptoms. Three patients required continuous alternate day prednisone for control of symptoms (corticosteroid-dependent idiopathic anaphylaxis). Of the 335 patients, there were no longer any patients with the diagnosis of malignant idiopathic anaphylaxis defined as requiring prednisone, 20 mg daily, or 60 mg every other day, for control of idiopathic anaphylaxis. Of the six patients previously diagnosed with malignant idiopathic anaphylaxis, five no longer required prednisone and one has a decreased prednisone requirement of 20 mg on alternate days. Hospital visits were significantly reduced by the management regimens. There were no fatalities from idiopathic anaphylaxis in this series.

CONCLUSIONS

The incidence of idiopathic anaphylaxis is increasing in our practice with more patients being evaluated each year. During 1104 patient years of observation (the longest period of single patient observation being 24 years), no inciting agent has been found responsible for the anaphylactic symptoms. Prognosis continues to remain good with the majority of patients achieving remission with pharmacotherapy.

Undifferentiated somatoform idiopathic anaphylaxis: nonorganic symptoms mimicking idiopathic anaphylaxis

BACKGROUND

Northwestern University's Division of Allergy and Immunology has had experience with the diagnosis and treatment of more than 350 patients with idiopathic anaphylaxis (IA). In 1992 we reported a group of patients with IA whose presentations mimicked IA, but IA and other organic causes were later excluded. Psychologic factors were suspected as the underlying problem. These patients were classified as IA-variant. Management of these cases was extremely difficult. There was significant morbidity and high and unnecessary costs.

OBJECTIVE

We aim to distinguish the nature of this disease and to highlight the evaluation and treatment of this group of patients.

METHODS

Their cases are reviewed and reported.

RESULTS

Common features included (1) presenting symptoms mimicking IA, (2) no objective findings that correlated with 1, (3) no response to the therapeutic regimen for IA, (4) meeting the Diagnostic and Statistical Manual of Mental Disorders criteria for undifferentiated somatoform disorder, and (5) significant wasted health care expenditure.

CONCLUSIONS

This group of patients were better defined as having undifferentiated somatoform-IA. An algorithm was proposed to expedite the diagnosis of the disease so that with early recognition of the disease, unwarranted repetitive consultations, tests, and inappropriate therapy can be avoided.