Journal Club

October 1, 1999

Family pet may protect against allergies

Family pet may protect against allergies

JOURNAL CLUB

COMMENTARIES BY MICHAEL G. BURKE, MD

Children exposed to cats and dogs during the first year of life are less likely to have allergic rhinitis at 7 to 9 years of age or asthma at 12 to 13 years of age than children who do not have this exposure. A second finding from this study, conducted among more than 2,000 school children in Sweden, is that the more siblings a child has the less likely he or she is to develop these allergies.

Investigators used a questionnaire to determine the prevalence of allergic diseases and various background factors in study subjects. In 1991, when children in the study were 7 to 9 years old, the researchers asked parents questions like these: Has your child ever had asthma/wheezy bronchitis, allergic rhinitis/conjunctivitis, eczema, or urticaria/allergic congestion? Did the child have any symptoms last year? They also asked about exposure to dogs or cats and the number of respiratory tract infections the child had during the first year of life. The following year, investigators conducted a validation interview with 412 children, who also received skin prick tests. This subgroup participated in a follow-up study four years later as well. Parents of these children were asked questions identical to those asked in 1991 about clinical symptoms and queried in detail about their children's early pet exposure, and the children received skin prick testing.

According to survey results, school children who were exposed to pets during the first year of life and who had more siblings were less likely to have respiratory tract allergy than other children. In addition, children exposed to cat during the first year of life had fewer positive skin prick tests to cat than children who were not exposed to cat. At 12 to 13 years of age, fewer children exposed to pets during the first year of life were asthmatic and sensitized to cat than children who were not exposed to cat. These differences remained even when investigators excluded from the analysis 91 children whose families had decided against keeping a pet because of allergy in the family (Hesselmar B et al: Clinical and Experimental Allergy 1999;29:611).

Commentary: I am not convinced. When families who say they chose not to have a pet because of family history of allergies were excluded from analysis, the authors were still able to show decreased prevalence of asthma at follow-up. Decreases in cumulative incidence of asthma and in prevalence of rhinitis were no longer statistically significant, however. I am still keeping these allergens out of my house.

Alternative treatment often an adjunct

Alternative health care frequently is used as an adjunct to conventional treatment but does not significantly affect clinical outcomes in children hospitalized with common acute medical illnesses, a study from New Zealand shows. Investigators followed 251 children hospitalized with asthma, pneumonia, bronchiolitis, gastroenteritis, or fever. Parents of the children were questioned about use of alternative health care as an adjunct to conventional treatment.

Eighteen percent of children had received complementary treatment during their current illness and 29% at some time during their lives. Most of the children (77%) had been seen in primary care before being hospitalized. Those who were prescribed medication were significantly more likely than those who were not to receive complementary treatment (59% compared with 39%). Types of complementary treatment varied with the ethnicity of the child (the children were of European, Maori, or Pacific descent) and included homeopathy, naturopathy, chiropractic, aromatherapy, spiritual healing, oil massage, and herbal remedies. Differences between users and nonusers of alternative health care differed little as to severity of illness at presentation, investigations performed, treatment administered, or length of inpatient stay (Armishaw J et al: Arch Dis Child 1999;81:133).

Commentary: The use of complementary therapies is not restricted to children from New Zealand. It is becoming clear that many of our patients' parents are sophisticated shoppers for alternative therapies. I think that we are obliged to know what complementary therapies are being used on our patients and to learn what we can about how these modalities can benefit or harm them.

KD diagnosis may not meet standard criteria

Physicians increasingly are diagnosing Kawasaki disease (KD) in patients who do not meet the diagnostic criteria of the American Heart Association (AHA). This practice is justified, authors of a new study suggest, because of continuing reports of "incomplete" KD associated with coronary artery abnormalities. Diagnosis of KD with an incomplete clinical picture does not appear to result in earlier treatment and a better outcome, however.

Investigators did a retrospective review of 127 patients who were discharged from a tertiary care children's hospital from 1991 to 1997 with a diagnosis of KD. All patients received intravenous immunoglobulin (IVIG) and had complete echocardiograph studies. Eighty one (64%) of the patients met AHA criteria for KD and 46 (36%) did not. During 1995 to 1997, many more patients did not meet AHA criteria than during 1991 to 1994 (45% vs. 27%). Infants 12 months old or younger were far more likely than older children to carry a diagnosis of KD without meeting the criteria. Children who did not meet criteria did not receive IVIG sooner than those who did meet the criteria. Further, more of the patients who did not meet the criteria developed coronary artery abnormalities than those with the full clinical picture of KD (20% compared with 7%) (Witt MT et al: Pediatrics 1999;104[1]:e10).

Commentary: Each year brings a few more descriptions of coronary artery disease in incomplete KD. Who can blame clinicians for having a low threshold to treat? We still need a good diagnostic test for KD.

Acute chest syndrome underestimated in SCD

Using history and physical examination alone, clinicians grossly underestimate the presence of acute chest syndrome (ACS) in febrile patients with sickle cell disease (SCD), according to a new study.

During a one-year period, clinicians evaluated 73 patients with SCD who presented to the emergency department a total of 96 times with a temperature of at least 38° C. Clinicians noted on a questionnaire each patient's physical signs and symptoms and the clinician's impressions about the presence of ACS. All patients then underwent chest X-ray. The evaluating physician or nurse practitioner did not suspect ACS in 14 (61%) of the 23 patients whose X-ray revealed ACS. In addition, of 73 patients with normal X-rays, 12 (16%) were incorrectly identified as having ACS based on clinical findings. Increasing years of clinical experience did not significantly improve clinicians' ability to diagnose ACS—attending physicians missed 60% of ACS cases they evaluated.

With the exception of splinting, no vital sign, symptom, or physical examination finding helped to distinguish patients with and without ACS. In addition, 57% of patients with ACS had completely normal findings on physical examination, and the presentation of patients with clinically detected ACS did not differ significantly from that of clinically unsuspected ACS. Length of hospitalization, oxygen use, and need for transfusion also were the same in patients whose ACS was suspected by clinicians and in those whose condition initially was undetected. Given the mortality and morbidity associated with ACS, investigators concluded that clinicians should not hesitate to obtain empiric chest radiography when evaluating febrile patients with SCD (Morris C et al: Ann Emerg Med 1999;34:64).

Commentary: It is pretty rare these days to see a study that supports increased use of a diagnostic test, especially when clinical suspicion of disease is low. Here, though, the authors suggest a chest X-ray in virtually all febrile children with SCD. I will follow their suggestion while wondering what happened to all those patients who were sent home without X-rays. I imagine that some had infiltrates but never returned with progression of pulmonary disease.

Cost-effective treatment of strep throat

A cost-effectiveness analysis of strategies for management of children older than 3 years with pharyngitis shows that throat cultures are preferable to rapid streptococcus antigen tests. Investigators used a decision-analysis model, incorporating data on the probability of streptococcal pharyngitis and the risks and benefits associated with testing and treatment, to examine the short-term costs and cost-effectiveness of seven strategies:

  • Neither test nor treat (do nothing)

  • Perform an enzyme immunoassay (EIA) rapid test. If results are positive, prescribe penicillin V—250 mg orally three times a day for 10 days; if results are negative, do nothing (EIA only)

  • Perform an EIA rapid test. If results are negative, obtain a culture; if findings of either test are positive, prescribe penicillin (EIA/culture)

  • Perform an optical immunoassay (OIA) rapid test. If results are positive, prescribe penicillin; if results are negative, do nothing (OIA only)

  • Perform an OIA rapid test. If results are negative, obtain a culture; if findings of either test are positive, prescribe penicillin (OIA/culture)

  • Obtain a culture. If results are positive, prescribe penicillin (culture)

  • Treat empirically (empiric therapy)

Of the four office-based strategies, "culture" was the least expensive at $8.20 a patient, followed by "do nothing" ($9.57), "empiric therapy" ($11.62), and "OIA only" ($11.72). In addition to being the least expensive, the culture strategy was the most effective, given the assumed prevalence of streptococcal pharyngitis (20.8%) and the rheumatic fever attack rate. The authors recommend managing a sore throat in an office setting with antibiotic therapy guided by the traditional throat culture with tests performed in a local reference laboratory. This assumes the patient complies with the treatment regimen. They also prefer the "culture" strategy if amoxicillin is substituted for oral penicillin. Office-based OIA testing is an economically reasonable alternative strategy (Tsevat J et al: Arch Pediatr Adolesc Med 1999;153:681).

Commentary: What seems like a simple question becomes pretty complicated when seasonal swings in strep prevalence, issues of compliance and follow-up, and concerns of busy parents are all thrown into the mix. I think that you are left with deciding which approach to pharyngitis makes sense for each patient, each day.

Periodic fever syndrome has no long-term effects

A new study sheds some light on a periodic fever syndrome in children. The condition, which has the acronym PFAPA, is characterized by periodic fever, aphthous stomatitis, pharyngitis, and cervical adenitis. To learn more about the presentation, clinical course, therapeutic response, and long-term effects of this condition, investigators evaluated medical records and other information on 94 patients who were found to have PFAPA during a 10-year period and followed up with telephone calls to determine the persistence of episodes and sequelae. The interval between the initial evaluation and the follow-up survey ranged from less than one month to 9.4 years, with a mean of 3.3 years. At follow up, the mean age of the 83 available patients was 8.9 years.

PFAPA episodes persisted for several years, during which symptoms and frequency—episodes lasted a mean of 4.8 days and occurred every 28 days— were unchanged. Before the attacks stopped entirely, they were less frequent but did not change in character. Glucocorticoids were very effective in controlling symptoms, and tonsillectomy and cimetidine treatment were associated with remission in a few children. A few patients continued to have episodes after age 17 years, but symptoms were milder and the episodes less frequent. PFAPA appeared to produce no long-term effects. The authors note that the syndrome is easily recognized by the predictable recurrence of fevers at intervals of three to six weeks and the associated symptoms of pharyngitis, aphthous ulcers, and cervical lymphadenopathy (Thomas KT et al: J Pediatr 1999;135:15).

Commentary: These authors described this entity in 1987. Now they report on their more than 10 years of experience to define the symptoms, natural history, and differential diagnosis for the PFAPA syndrome. It is worth reading this article and the accompanying editorial. They will prepare you to identify these patients, to offer some symptomatic treatment, and to reassure parents about long-term outcome.

Good screening tool for esophageal coins

According to a new study, metal detectors, even in the hands of relatively inexperienced operators, are effective in confirming a suspected coin ingestion and determining if the coin is located in the esophagus. Resident and attending physicians in the emergency department of a pediatric hospital evaluated 62 children believed to have ingested coins. They used a hand-held metal detector after a one-minute demonstration. A follow-up radiograph confirmed metal detector findings and the location of the coin. Radiographs and metal detection also were used to determine coin location in an additional 29 patients who had been referred with a known coin ingestion. The 91 children in the study ranged in age from 9 months to 17 years.

The metal detector correctly identified 53 of the 54 coin ingestions in the 62 children initially evaluated. Based on the auditory signals the metal detector emitted, physicians also correctly identified 42 of 44 esophageal coins, which can produce life-threatening complications. Investigators concluded that metal detection is a good screening test for the presence of an ingested coin and can accurately determine if an ingested coin is located in the esophagus (Bassett KE et al: Am J Emerg Med 1999;17:338).

Commentary: It sounds as if this technique is easy and quite reliable. It may also save a few X-rays in the emergency department, decreasing radiation exposure and keeping a little more change in parents' pockets.

Also of note

How often do pediatricians refer? According to a prospective study of referrals made by 142 pediatricians in a primary care practice-based research network, only about one in 40 pediatric visits results in referral, while additional referrals, accounting for about one quarter of all referrals by pediatricians, are made during telephone conversations with parents. Of 58,771 office visits nationwide over 20 consecutive practice days, referrals were made only 1,854 times. The most common reason for referral was for advice on diagnosis or treatment. Another important reason was to obtain a specialized skill in an area such as surgery, nonsurgical technical procedures, specialized medical management, or mental health counseling. About half of all referrals for advice on diagnosis or treatment and nearly two thirds of mental health referrals were made during the patient's first office visit for the health problem. Physicians requested a consultation or a referral with shared management about three quarters of the time. Otitis media (9.2%) was referred to specialty care more frequently than any other condition. Probability of referral during an office visit increased with patient age, and boys were referred more often than girls (Forrest CB et al: Arch Pediatr Adolesc Med 1999;153:705).

Medicating ADHD does not lead to substance abuse. Investigators assessed the risk for substance use disorders (SUDs) in boys with and without attention deficit hyperactivity disorder (ADHD), and in boys with ADHD who do and do not take psychotropic medication. They compared the incidence of SUD throughout adolescence in 56 children with ADHD who took medication, 19 children with ADHD who had not taken medication, and 137 children who did not have ADHD. Investigators restricted their analysis to male subjects older than 15 years because of possible confounding factors.

Children with ADHD who had not taken medication were significantly more likely at follow-up to have a SUD—related to alcohol, marijuana, hallucinogens, stimulants, cocaine, or tobacco—than control subjects without ADHD. Children with ADHD who had been taking medication at the start of the study were significantly less likely to have a SUD at follow-up than children with ADHD who had not been treated with medication—even when accompanying conduct disorder was taken into account. The ADHD group that was medicated had only a slightly higher risk for tobacco addiction or dependence than the unmedicated ADHD group, which was not at significantly more risk than control subjects (Biederman J et al: Pediatrics 1999;104 [2]:e20).



Iris Rosendahl. Journal Club. Contemporary Pediatrics 1999;10:185.