Cast remains the standard retention treatment for fractures, especially upper extremity fractures(1). However, there are various complications related to this type of retention including compartment syndrome, pressure sores, stiffness, and pruritus(2-5). Despite being considered a minor complication, pruritus associated with a cast can disturb the patient’s quality of life and in some instances result in premature cast removal or infection. One previous study found that significant pruritus during cast retention occurred in about 71% of cases(3). Currently, the pathomechanism of pruritus during cast retention remains unknown. A number of factors such as humidity, irritants, or hypersensitivity have been postulated. Some studies have hypothesized that the histamine-release pathway can produce itching(5-9).

In our current practice in Thailand, most orthopedists apply talcum powder before affixing the cast to try to prevent pruritus. Calamine lotion is another potential candidate to reduce this

Correspondence to : Tangtrakulwanich B, Department of Orthopaedic Surgery, Faculty of Medicine, Prince of Songkla University, Hat Yai, Songkhla 90110, Thailand.

E-mail: boonsin.b@psu.ac.th

JRCOST VOL.34 NO. 3-4 July-October 2010

problem due to its coolness and antihistamine effect. However, there have been no previous studies evaluating the efficacy of calamine lotion in reducing pruritus associated with casts. The objective of this study was to compare the efficacy of talcum powder vs. calamine lotion in reducing pruritus associated with casts.

Material and Method

This study was approved by the Ethics Committee of the Faculty of Medicine, Prince of Songkla University. Informed consent was obtained from all patients before the study. Patients aged between 15-80 years visiting the Emergency Department of our institution with closed fracture of the distal radius from June 2008 to June 2009 were included in this study. Simple randomization using opaque envelope was used to randomize the patients into two groups: those given talcum powder and those given calamine lotion to reduce pruritus.

All patients were treated with closed reduction and a short arm cast by the on-call senior resident. After the reduction, the skin was cleaned with 70% alcohol, and either talcum powder (15

grams) or calamine lotion (15 ml) was applied before cast application. All patients were informed about cast care and requested to report the level of pruritus (0-10) daily in the diary, which was provided for them. All patients received Atarax and paracetamol for use as rescue medication. The patients were followed up at the second week for cast changing and then every week until cast

removal. When the cast was removed, the skin condition was inspected by the same senior resident, and the patient was asked to rate his or her satisfaction with the overall result of treatment.

2

Statistical analysis

Descriptive analysis was used to evaluate the demographic characteristics. Paired t-test was used to compare mean pruritus scores between the groups at different time points. Chi-Square was tested for all categorical outcomes.

Results Pruritus score	Calamine lotion	Talcum powder	P-value
Day 1	0.5 ( 1.4 )	0.5 ( 0.9 )	0.985
Day 7	1.8 ( 1.7 )	2.1 ( 1.5 )	0.645
Day 14	1.5 ( 2.1 )	2.1 ( 1.3 )	0.340
Day 21	1.7 ( 1.6 )	2.1 ( 2.3 )	0.595
Day 28	1.0 ( 1.2 )	2.0 ( 1.7 )	0.030*
Mean usage of rescue medication	1.9 ( 4.8 )	1.3 ( 3.8 )	0.677

 

Kalamin antihistaminik kıyaslaması

 

Itching Like Crazy: Understanding Chickenpox

Brice Labruzzo Mohundro, PharmD, BCACP
Assistant Professor
University of Louisiana at Monroe
College of Pharmacy
Baton Rouge, Louisiana

Alexis Horace, PharmD
Assistant Professor
University of Louisiana at Monroe
College of Pharmacy
Baton Rouge, Louisiana

3/20/2012
US Pharm. 2011;37(3):58-60.

With the advent and progression of new vaccines in the pharmaceutical market, some may come to believe that varicella-zoster virus (VZV), also known as chickenpox, has been eradicated and therefore is no longer a health care concern. Since the release of the varicella vaccine in 1995, there has been a significant decrease in infection rates. Deaths and the number of hospitalizations due to infection with VZV have decreased by 90% since 1996.¹ However, the CDC reports that from 2001-2005, there were outbreaks in schools that reported vaccination coverage of 96% to 100%. In this population, approximately 11% to 17% of children vaccinated for VZV had a breakthrough infection. Most adults prior to the establishment of the varicella vaccine were thought to have acquired immunity as a consequence of having VZV as a child.¹ The CDC states that most breakthrough infections occurred in adolescence; however, adults who received the vaccination in childhood may be at possible risk.¹

VZV is extremely contagious.¹ Transmission of VZV relies on human vectors that expose one another to infected respiratory secretions or direct contact with lesions.^1,2 Clinical manifestations include malaise, headache, and low-grade fever.³ Children typically develop a rash prior to these symptoms; however, adults develop a rash 1 or 2 days after.¹ Purulent lesions occur mostly on the face and trunk of the body, and they may also appear on various mucous membranes.¹ The rash evolves over several days with multiple stages of the lesions in development.¹ Breakthrough infections typically have fewer lesions and are mild, resolving in a few days.⁴

VZV is typically self-limiting in healthy children; however, complications include secondary bacterial super infection, central nervous system involvement, and Reye’s syndrome.^1,2 Pneumonia is a complication that often occurs in adults.⁵ A person’s age correlates with the risk of developing possible complications. Those younger than 1 year of age or greater than 20 years of age develop these complications more frequently.¹

Treatment

Primary infection of VZV is usually self-limiting in healthy children, often only requiring symptomatic treatment for relief of itching. Although no studies exist evaluating the effectiveness of calamine lotion in patients with itching due to VZV, it may be recommended owing to its safety profile and patient or caregiver reported relief.⁶ Other symptomatic treatments include antipruritic lotions such as those containing camphor and menthol (e.g., Sarna Anti-Itch), oatmeal baths, cool or wet compresses, and tepid baths.^2,7 Oral antihistamines including hydroxyzine, loratadine, cetirizine, fexofenadine, and diphenhydramine may help with itching and prevent excoriation from occurring.^2,7 Ensuring fingernails are kept short also will help to prevent excoriation. Several reports of topical diphenhydramine toxicity exist in patients with varicella; therefore, it should not be recommended for use, especially in combination with oral diphenhydramine.^8-10 Use of salicylates during a varicella infection increases the risk of acquiring Reye’s syndrome; thus acetaminophen and other antipyretics, not including aspirin, should be recommended for fever.^2,7

While VZV is usually self-limiting, there are several instances in which antiviral treatment is indicated. Both the Advisory Committee on Immunization Practices (ACIP) and American Academy of Pediatrics (AAP) do not recommend antiviral therapy for healthy children without complications. The AAP does suggest, however, that those at increased risk of moderate-to-severe VZV primary infection be considered for antiviral treatment with acyclovir. These groups include healthy individuals ≥12 years old, pregnant women with serious, viral-mediated complications such as pneumonia, those with chronic cutaneous or pulmonary disorders (e.g., asthma), and persons receiving long-term salicylate therapy or short, intermittent, or aerolized courses of corticosteroids. For best results, antiviral therapy should begin within 24 hours of rash onset (TABLE 1).¹¹

 

Varicella zoster immune globulin (VZIG) is a varicella-specific immune globulin used to produce passive immunization for the treatment of exposed, susceptible individuals who are at risk of complications from VZV.¹² The CDC recommends VZIG within 96 hours of exposure for pregnant women, neonates, and immunocompromised persons at high risk of developing VZV and complications.¹ Persons who received two doses of varicella vaccine and then became immunocompromised are not candidates for VZIG.¹

Prevention

Two varicella-containing vaccines are available in the United States for use in children 12 months and older to prevent the occurrence of VZV (TABLE 2). Varivax (Merck) is a single-agent vaccine, while ProQuad (Merck) is a combination measles-mumps-rubella and varicella (MMRV) vaccine. Also available in the U.S. is Zostavax (Merck), a herpes zoster vaccine FDA approved for persons aged 50 or older to prevent postherpetic neuralgia caused by the reactivation of VZV. Although this product is approved for use in those ≥50 years, ACIP recommendations only recommend it for those ≥60 years.^12,13

 

All three varicella-containing vaccines contain live attenuated virus derived from the Oka strain of VZV but in varying amounts. Single-agent varicella vaccine has a lower VZV titer than the titer in the MMRV product, and the herpes zoster vaccine contains the highest titer of all three products. The Oka strain of VZV was isolated in the early 1970s from blister fluid in a healthy child infected with VZV. The varicella single-agent vaccine has been available for use in Asia since 1988 and in the U.S. since 1995. In 2005, the combination MMRV vaccine was approved for use in the U.S. Following the approval of the MMRV vaccine was the herpes zoster vaccine, which was approved in 2006.¹³

The varicella vaccine has a seroconversion rate of 97% in children ages 12 months to 12 years after one dose with 90% of those maintaining antibody 7 to 10 years after receiving the vaccination. The seroconversion rate is estimated to be 78% in persons 13 years of age or older after one dose and 99% after two doses (second dose given 4-8 weeks after initial dose), with 97% of those receiving two doses maintain antibody for at least a year. The vaccine is 70% to 90% effective against VZV infection, and 90% to 100% effective against moderate or severe disease.¹³ Even with these positive seroconversion rates, breakthrough VZV infection has been reported. Data from Merck’s routine global postmarketing surveillance system and the Varicella Zoster Virus Identification Program over a 10-year time frame indicate approximately one breakthrough per 10,000 distributed doses occurred, with 51 cases meeting the regulatory definition of serious (1%). Breakthrough VZV infections occurring 142 days after vaccination were associated with wild-type VZV; however, 99% of the reports were not serious in nature, according to regulatory definition.¹⁴

Despite the effectiveness of the varicella vaccine, there are adverse effects associated with its use. The 10-year data discussed previously suggests there were 3.4 reports of adverse events for every 10,000 doses administered. It is estimated that approximately 55.7 million single-agent varicella vaccine doses were distributed worldwide during this time.¹⁴ The most common adverse reactions following administration of the vaccine include local reactions and generalized rash. Systemic adverse reactions are uncommon with the varicella vaccine. Local reactions, mostly of mild and self-limiting nature, include pain, soreness, erythema, and swelling at the injection site, which are reported by 19% of children and 24% (33% after the second dose) of adolescents and adults.¹³ Varicella-like rash, both injection site and generalized rash, have been reported following vaccination. Most rashes are maculopapular instead of the usual characteristic vesicular varicella rash. The injection-site rash has been reported by 3% of children and 1% of adolescents and adults (after second dose), while the generalized rash has been reported by 4% to 6% of those receiving the varicella vaccine. The injection-site rash has a median of two lesions present and the generalized rash occurs with an average of five lesions. Injection-site lesions usually appear within 2 weeks after vaccine administration while generalized rashes are typically seen within 3 weeks.¹³

Although systemic reactions are uncommon, fever is reported by 15% of children and 10% of adolescents and adults within 42 days after receiving the varicella vaccine.¹³ However, most of these reported fevers have been associated with concurrent illness and not the vaccine itself. Postmarketing surveillance also reported neurologic adverse events including 12 reports of encephalitis, 5 reports of meningitis, and 5 reports of cerebellar ataxis.¹⁴ Because varicella is an attenuated live vaccine, the potential for secondary transmission to household contacts is a concern.¹³

Adverse reactions are similar in patients receiving the MMRV vaccine.¹³

In 2006, the CDC implemented a routine two-dose childhood varicella vaccination program.¹ The CDC decided to change from the one-dose program to two doses after reviewing epidemiologic data from the one-dose program. When comparing the one-dose to two-dose schedules, it was noticed that the two-dose schedule was more effective at preventing VZV disease. Catch-up vaccinations for children and adolescents who only received one dose of varicella are recommended, as well as two doses for adolescents and adults without evidence of varicella immunity.¹

Although live attenuated vaccines are not routinely recommended for immunocompromised patients, the CDC recommends varicella vaccine be administered to those with isolated humoral immunodeficiency and patients with leukemia, lymphoma, or other malignancies whose disease is in remission and who are ≥3 months post-chemotherapy treatment. Varicella vaccination should also be considered in HIV-infected children if their CD4+ T-lymphocyte percentage is ≥15%. If children meet these criteria, they should receive two doses of single-antigen varicella vaccine 3 months apart. Varicella vaccination may also be considered in HIV-infected persons with CD4+T-lymphocyte counts ≥200 cells/mL.¹

Conclusion

Though the VZV vaccine is available, there is still a very small occurrence of breakthrough infection. In comparison to prevaccination statistics, the incidence of infection has decreased significantly. Therefore, importance lies in parents maintaining updated vaccinations for their children. This not only prevents the spread of infection, but also decreases the severity of those who may be infected.⁴ A person who experiences a breakthrough infection after receiving varicella vaccine may still infect a healthy person with wild-type virus.¹⁴ It has been established that the VZV vaccine is approximately 95% effective in clinical practice.⁴ However, should a patient experience a primary or breakthrough infection, there are treatments available to reduce the course of the disease and treat symptoms.

REFERENCES

1. CDC. Prevention of varicella: recommendations of the Advisory Committee on Immunization Practices (ACIP). MMWR Recomm Rep. 2007;56(No. RR-4):1-40.
2. Carrasco DA, Straten MV, Tyring SK. Treatment of varicella-zoster virus and postherpetic neuralgia. Dermatol Ther. 2000;13:258-268.
3. Whitely R. Varicella-zoster virus. In: Galasso G, Whitely R, Merigan T, eds. Antiviral Agents and Viral Disease in Man. New York, NY: Raven Press; 1990:235.
4. Vazquez M, LaRussa P, Gershon A, et al. The effectiveness of the varicella vaccine in clinical practice. N Engl J Med. 2001;344:955-960.
5. McKendall R, Klawans H. Nervous system complications of the varicella-zoster virus. In: Vinken P, Bruyn G, eds. Handbook of Clinical Neurology. Vol. 34. Amsterdam, Netherlands: Elsevier; 1978:161.
6. Tebruegge M, Kuruvilla M, Margarson I. Does the use of calamine or antihistamine provide symptomatic relief from pruritus in children with varicella zoster infection? Arch Dis Child. 2006;91:1035-1036.
7. Habif TP. Warts, herpes simplex and other viral infections. In: Clinical Dermatology. 5th ed. New York, NY: Mosby Elsevier; 2010. www.mdconsult.com. Accessed December 27, 2011.
8. Chan CY, Wallander KA. Diphenhydramine toxicity in three children with varicella-zoster infection. DICP. 1991;25:130-132.
9. Woodward GA, Baldassano RN. Topical diphenhydramine toxicity in a five year old with varicella. Pediatr Emerg Care. 1988;4:18-20.
10. McGann KP, Pribanich S, Graham JA, Browning DG. Diphenhydramine toxicity in a child with varicella. A case report. J Fam Pract. 1992;35:210, 213-214.
11. Chickenpox (varicella). Managing persons at risk for severe varicella. CDC. www.cdc.gov/chickenpox/index.html. Accessed December 27, 2011.
12. Facts & Comparisons. Facts & Comparisons eAnswers [online]. Wolters Kluwer Health, Inc.; 2011. www.factsandcomparisons.com/facts-comparisons-online.aspx. Accessed January 2, 2012.
13. CDC. Varicella. In: Atkinson W, Wolfe S, Hamborsky J, ed. Epidemiology and Prevention of Vaccine-Preventable Diseases. 12th ed. Washington, DC: CDC; 2011.
14. Galea SA, Sweet A, Beninger P, et al. The safety profile of varicella vaccine: a 10-year review. J Infect Dis. 2008;197(suppl 2):S165-S169.
15. Lexi-Comp [iPhone app]. Hudson, OH: Lexi-Comp, Inc.; 2010. Accessed January 2, 2012.

To comment on this article, contact rdavidson@uspharmacist.com

Kalaminin böcek sokmasında mitigatörle kıyası

Wilderness and Environmental Medicine, 17, 21 25 (2006)

ORIGINAL RESEARCH

Treatment of Imported Fire Ant Stings With Mitigator

Sting and Bite Treatment—A Randomized Control Study

David C. Hile, MD; Troy P. Coon, MD; Carl G. Skinner, MD; Lisa M. Hile, MD; Phillip Levy, MD;

Manish M. Patel, MD; Michael A. Miller, MD

From Darnall Army Community Hospital, Fort Hood, TX (Drs Hile, Coon, Skinner, Levy, Hile, and Miller); Wayne State University–Detroit

Receiving Hospital, Detroit, MI (Dr Levy); and Emory University, Atlanta, GA (Dr Patel).

Objective.—To evaluate the efficacy of the commercially available product Mitigator Sting and

Bite Treatment in reducing the pain after imported fire ant stings.

Methods.—Twenty-four volunteer subjects were exposed to imported fire ant stings on both forearms.

The subjects received Mitigator paste on 1 arm and calamine lotion on the opposite arm, in a

blinded manner, from 90 seconds to 10 minutes after exposure. Subjects recorded pain on a 100-mm

visual analog scale 60 seconds, 20 minutes, and 3 days after exposure. A 2-tailed paired t test was

used to compare the difference in reduction of pain over time between the Mitigator-treated arms and

the calamine-treated arms.

Results.—At 60 seconds, the mean visual analog scale pain score was 23.9 mm for the Mitigator

group and 24.5 mm for the calamine group. At 20 minutes, the mean score was 7.6 mm (_ _ 16.3)

for the Mitigator group and 12.7 mm (_ _ 11.8) for the calamine group. At 3 days, the mean score

was 2.4 mm (_ _ 21.5) for the Mitigator group and 2.9 mm (_ _ 21.6) for the calamine group.

There was no significant difference between groups for change in visual analog scale pain score at

60 seconds, 20 minutes (P _ .256), or 3 days (P _ .64).

Conclusions.—There was no significant difference in pain relief between calamine and Mitigator

for imported fire ant stings.

Key words: imported fire ant, Hymenoptera, calamine lotion, insect bites and stings, therapeutic techniques

and equipment, pain management, analgesia, Mitigator

Introduction

Imported fire ants (IFAs) are widely distributed across

the south-central and southeastern United States, having

been introduced from their native habitat in sub-Amazonian

South America many decades ago. By far, the

most common and widely distributed species is Solenopsis

invicta, the red IFA. In recent years, red IFAs

have also been discovered in New Mexico, in California,

and on many Caribbean islands, as well as in Australia

and New Zealand.1

This abstract was presented at the annual conference of the Society

for Academic Emergency Medicine, May 22 to 25, 2005, in New York,

NY.

There was no funding in the production of the above manuscript.

Mitigator product was provided courtesy of Mr Pat Kennedy of

www.mitigator.net. We are not aware of any conflicts of interest.

Corresponding author: David Hile, MD, 2014 Lakefront Dr, Harker

Heights, TX 76548 (e-mail: hile_16@yahoo.com).

It is estimated that IFAs sting more than 1 million

people in the United States annually, and tens of thousands

of people will seek medical treatment for allergic

and infectious complications related to these stings.2 The

severity of the stings can range from mild, local pustule

formation to rare cases of anaphylaxis in predisposed

individuals.3,4 Development of a local inflammatory response

is typical and may result in temporary debilitation.

In the wilderness, allergic or infectious complications

may create a potentially life-threatening situation.

Efforts to diminish the duration and severity of symptoms

once a person has been stung have not yielded

positive results.5–7 Mitigator Sting and Bite Treatment

(American Natural Technology Sciences, Rogers, AR) is

a recently developed paste that targets the local inflammatory

reaction associated with IFA stings. Mitigator is

hypothesized to work by rendering the IFA venom ineffective,

possibly by protein denaturation. Although anecdotal

evidence of successful IFA treatment with Mit22

Hile et al

Sting technique.

igator exists, no randomized trials have been conducted.

This study was therefore designed to investigate the clinical

benefit of Mitigator through comparison with a common

standard therapy.

Methods

This study was designed as a randomized, single-blind

comparison trial of IFA sting treatment with Mitigator

vs calamine lotion purchased from a Walgreens store.

Mitigator is considered safe and nontoxic when applied

topically. The main ingredients are water, walnut shells,

emulsifying wax NF, pentaerythrityl tetracappryate, isopropyl

palmitate, ceterearyl alcohol, polysorbate 60, sodium

bicarbonate, papain, alcohol denatured, sodium hydroxide,

methylparaben, propylparaben, and phenoxyethanol.

At the time of this writing, Mitigator costs approximately

$6 for 1 ounce of scrub in comparison with

$2.79 for 6 ounces of calamine lotion. Institutional review

board approval was obtained before study initiation,

and written informed consent was obtained from

all subjects.

Volunteer subjects were recruited by using publicly

displayed bulletins. Individuals who expressed interest

in the study were gathered at a single-day event. After

hearing an explanation of the intent and design of the

trial, those who were willing to participate were given a

health-screening questionnaire. All female subjects were

required to take a urine pregnancy test before participation.

Subjects who met the following inclusion criteria

were consented and enrolled: age 18 to 50 years with

prior exposure to IFA stings, absence of a serious medical

condition, absence of previous IFA stings or allergic

reactions to insect bites or stings, absence of asthma or

other reactive airway diseases, and absence of a known

allergy to walnuts. In addition, those willing to participate

had to ensure ability to attend a follow-up session

3 days later. Subjects who were pregnant or were regularly

using oral corticosteroids, anti-inflammatory

agents, or antihistamines were excluded.

Twenty-four enrolled subjects (7 [28%] women and

17 [68%] men) were exposed to IFA stings on a small

shaved area of both forearms with a small cup containing

10 live IFAs (Figure). Sting exposure was for 10

seconds, based on a rough estimation of time for a typical

IFA encounter. After exposure, the subjects were

allowed to remove the ants, as would be standard procedure

for a reasonable person. At 1 minute, all subjects

were given cards labeled ‘L’ (left) and ‘R’ (right) to indicate

body site. The cards contained a visual analog

scale (VAS), 100 mm in length, with ends labeled ‘‘most

pain’’ and ‘‘least pain.’’ The subjects were asked to draw

a line through the VAS indicating pain level before treatment

on each card, with response for each arm considered

independently. At 90 seconds after the stings, treatment

with 0.5 ounces of Mitigator paste was applied to

a randomly selected envenomation site (left or right forearm),

and standard 0.5 ounces of calamine lotion was

applied to the alternative arm. Subjects were blinded to

treatment allocation. Treatment randomization (right or

left) was predetermined by a coin flip. The paste or lotion

was vigorously rubbed into the affected area for 2

to 3 minutes, left in place for 10 minutes, and then rinsed

off as per the package instructions for Mitigator. At 20

minutes poststing, subjects were asked to repeat the pain

rating on another pair of 100-mm VAS cards labeled

‘‘L’’ and ‘‘R’’ without seeing their initial responses. Subjects

were then dismissed and allowed to treat the stings

as desired for the next 72 hours. At 72 hours, the subjects

returned for direct follow-up with study investigators

and completed a third set of VAS cards.

Baseline VAS responses were recorded and statistical

analysis was performed for the self-pairing study sample.

A 2-tailed paired t test (parametric) and the Wilcoxon

signed rank test (nonparametric) were used to compare

differences in pain-score change from 60 seconds

to 20 minutes and from 60 seconds to 3 days for grouped

data of the Mitigator- and calamine-treated arms. By using

13 mm as the statistically significant difference in

change of pain over time between groups, with a power

of 80% and a 2-tailed alpha of 0.05, we determined that

a minimum of 21 subjects would be needed. We also

used a random-effects repeated-measures analysis of

variance and found similar results as with the paired t

test (results not reported).

Results

Mitigator was placed on the left arm in 8 subjects and

on the right arm in 16 subjects, with calamine lotion

Treatment of Imported Fire Ant Stings 23

Table 1. Perceived pain (in millimeters) by individual subjects on the visual analog scale

Subject

Mitigator

60 s 20 min 3 d

Calamine

60 s 20 min 3 d

Table 2. Mean perceived pain (in millimeters) by each subject

as recorded on the visual analog scale

Time

Mean pain

Calamine Mitigator

Difference

(95% CI) P value

60 s

20 min

3 d

24.5

12.8

2.92

23.9

7.63

2.42

0.583 (_6.22, 7.39)

5.13 (_1.94, 12.2)

0.500 (_1.88, 2.88)

.861

.147

.668

applied to the opposite respective arm in each individual.

There were no systemic reactions to IFA stings or adverse

reactions to treatment. Within-group baseline VAS

scores (Table 1) were generally similar, with the exception

of subject No. 13. There were no significant between-

group differences in mean VAS scores at baseline,

60 seconds, or 3 days (Table 2). Mean change in VAS

scores over time was statistically equivalent between

groups (Table 3). Only 3 of the subjects described the

use of any at-home therapy between day 1 and their

follow-up visit: 2 subjects used oral diphenhydramine

and 1 subject used oral aspirin and topical 1% hydrocortisone

cream on both arms. Subject No. 9 sought

medical care for her IFA stings, which had resulted in

bilateral arm hives when she went to work at a local

hospital 1 hour after her participation. She was treated

with diphenhydramine orally and a 5-day prescription

for prednisone. She had no complications at her 3-day

follow-up visit.

Discussion

Although fewer than 20% of those who seek medical

attention for IFA envenomation (1% of all who receive

IFA stings) will require an intervention such as treatment

of local infection or systemic reaction,8,9 identification

of effective treatment for IFA stings is important. Venom

from IFAs is composed of a mixture of allergens and

alkaloids, which shares some similarities to other Hymenoptera

species.3,10,11 The humoral responses invoked

by the envenomation include neurogenic inflammation

and cytokine cascade initiation as well as the generation

of humoral antibodies.11,12 Adverse local reactions may

occur as a result, and there have been several case reports

of IgE-mediated anaphylaxis.4,10 Immunotherapy

24 Hile et al

Table 3. Mitigator vs calamine lotion mean decrease in pain (in millimeters) from the visual analog scale

Time Mitigator Calamine Difference (95% CI) P value

60 s to 20 min

20 min to 3 d

60 s to 3 d

16.3

5.21

21.5

11.8

9.83

21.6

4.54 (_3.53, 12.6)

_4.625 (_11.4, 2.12)

_0.083 (_7.00, 6.83)

.256

.150

.640

has emerged as a potential therapy for people with severe

allergic reactions, but no advances have been made

regarding treatment of local pain and inflammation. Multiple

cellular processes are involved in the pain response,

and once initiated, pharmacotherapeutic intervention is

difficult. Although prophylactic treatment may effectively

block similar processes, as demonstrated in a recent

trial involving Chrysaora fuscescens and Chiropsalmus

quadrumanus (jellyfish) envenomations,13 this is not a

practical approach for IFA stings, as exposure is rarely

anticipated. Consequently, interventions directed at minimizing

pain are needed.

Available data on the treatment of IFA envenomations

are limited, and the manner of appropriate management

is uncertain. We believe this study is the first to address

the treatment of IFA stings through a randomized clinical

trial. We chose to investigate a commercially available

product (Mitigator) in an attempt to substantiate

subjective reports of its efficacy. However, we were unable

to demonstrate any statistical difference in relief of

pain when Mitigator was compared with a standardized

regimen with calamine treatment, and the situation remains

unresolved.

There may be multiple etiologies for the lack of statistically

significant differences in this study. Although

our study population was small, the number needed to

show a clinical difference on our VAS was sufficient. In

a study of this type, one would expect a curvilinear decrease

in pain, with the greatest difference in treatment

effect initially. Although there was a ‘‘trend’’ toward a

decrease in the Mitigator-treated arm at 20 minutes, the

difference was not significant. We acknowledge that subject

No. 13 in our study had a wide variability in pain

at onset between the calamine- and Mitigator-treated

arms. However, excluding this subject from the database

and recalculating the data still failed to demonstrate a

significant difference between the 2 treatments. Among

the multiple possible reasons for this is the inability of

the clinical setting to adequately reproduce the natural

environment. As those who have been stung will recall,

IFAs frequently ‘‘attack’’ in unison, and a person may

easily receive 10 to 20 stings before the ants can be

removed. Although approximately 10 ants were present

in each container in this study, many subjects experienced

just 2 or 3 stings. Furthermore, it is likely that the

ants expended their venom during the collection process

and therefore may have had less venom available during

the study than in the natural environment. This may have

led to decreased initial pain in the study population, thus

decreasing the apparent treatment effect. Because the

initial pain described by the subjects was low, demonstration

of therapeutic benefit from Mitigator, if it exists,

may require more volunteers than this study enrolled.

Future studies may benefit from attempts to increase initial

pain levels either by increasing the total number of

stings or by ‘‘resting’’ the IFAs for a number of days to

ensure that high levels of venom are present in the study

ants.

Conclusion

There was no demonstrable difference in immediate or

delayed pain relief between Mitigator and calamine lotion

therapy for IFA stings. These envenomations remain

a source of potential morbidity, and further investigation

into appropriate treatment is needed.

Acknowledgments

We thank the Brooke Army Medical Center Institutional

Review Board for reviewing and approving this study.

Mitigator Sting and Bite Treatment was provided upon

request for this study by Mr Pat Kennedy and American

Natural Technology Sciences, Rogers, AR; however, no

financial relationship exists between the investigators

and the manufacturer or distributors of Mitigator Sting

and Bite Treatment.

References

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Kaynak: Kalamin