Category Archives: Drug Allergy

Dealing with Problems by Self-Medicating

Couldn’t say it better for allergy & asthma meds!

123MyMD

Dealing with Problems by Self-Medicating

How many of us try to self-medicate ourselves. We might do it with alcohol; we might do it with drugs; we may do it with over-the-counter medications; we may do it with caffeine. All sorts of things are used to self-medicate. What you have to look at is what problem are you dealing with, and how are you trying to handle it? Self-medication is not a bad thing if you’re taking a cough medicine for a cold. But if you’re trying to grapple with something that’s beyond your skill, you need to get help. That’s why it’s important to see a doctor and get that advice.

For more information, please go to http://www.123MyMD.com.

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Antihistamine Guide

I’ve published stories about allergy to antihistaminesin the past…this guide is much more comprehensive!

PharmacistAnswers

Hello all!

Our antihistamine guide on pharmacistanswers.com is complete and posted for everyone to see!

Check it out: http://pharmacistanswers.com/antihistamine-guide.html

Article Excerpt:

Have you ever walked into your local drug store just to grab an allergy medicine and became instantly overwhelmed with all the choices in front of you? In this guide, we will hopefully simplify your options and give you a better idea of just what medication is the best choice for you.

 

What exactly is “histamine” and why does it cause such annoying symptoms?

 

Histamine plays a central role in the allergic response and it’s main purpose is not to simply cause the symptoms we hate so much (although it feels like that sometimes!). It’s effects on the blood vessels in our body and in our airways is what usually causes the most grief. Histamine also has a major role in the release of stomach acid and the…

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Tell Me Which Pain Meds I’m Allergic To!

It’s not unusual for a doctor to refer a patient to our allergy clinic to answer the question, “what pain medications am I allergic to?”  Surgery of any kind is a bit frightening, but add to that an adverse reaction to one of your pain medications and you know what hits the fan!  Reactions can include hives, difficulty breathing, headaches and a whole lot more.  So what can I do if I’m in a car accident or emergency surgery and I receive a pain medication I’m allergic to?  Will it kill me? 

Consider the following:

  1. Most effective pain meds are opioids and release histamine from the body when taken as pain meds.  We can’t skin test to medications in this category, so we rely on previous history.  That works well for the most part, but “there’s a first time for everything”
  2. The one exception to the above rule is fentanyl.  With this medication, skin testing and treatment for tolerance have been published and offer a good alternative.
  3. Often a procedure called “drug provocation testing (DPT)” is necessary to determine what you can and cannot take for pain medication.  Fortunately, most patients can tolerate the standard protocols used by most hospitals, so no need to worry.  If in doubt, DPT will give you VERY small amounts of medication making sure you can tolerate the drug before moving to a higher dose.  With a little patience & a long afternoon in the doctor’s office, we can usually find a medication that will work.
  4. But don’t take my word for it….the American Academy of Allergy Asthma & Immunology has several references on the subject of allergy to pain meds.  Check it out with the link below:

Prevention of allergic reactions in a patient scheduled for knee replacement who has a history of pain medication allergy and possible contact dermatitis to chromium.

I usually don’t trash talk, but….

 You should be concerned about the effects of asthma medication on the developing fetus; fortunately, birth defects are rare and often overstated, but you always have to maintain vigilance for new developments.
 
Why the concern about atresia? 
 

Maternal Asthma Medication Use May Cause Certain Birth Defects

Approximately 4% to 12% of pregnant women have asthma. Current clinical guidelines recommend that women with asthma maintain asthma therapy use during pregnancy. These medications act in 2 ways: as bronchodilators or anti-inflammatories. Few studies have examined the effects of maternal asthma medication use on birth defects.

The aim of this study by Lin and colleagues was to examine whether maternal asthma medication use during early pregnancy increases the risk for selected birth defects.  (Pediatrics. Published online January 16, 2012)

Study Synopsis and Perspective

A recent study found a statistically significant increase in the risk for isolated esophageal atresia, isolated anorectal atresia, and omphalocele in infants whose mothers used asthma medications within the month before conception or during the first 3 months of pregnancy.

Shao Lin, PhD, from the Center for Environmental Health, New York State Department of Health, Troy, and colleagues reported their study results in an article published online January 16 in Pediatrics.

The researchers used data collected for the National Birth Defects Prevention Study, an ongoing, multicenter, population-based, case-control study of the causes of birth defects that has been collecting data from 10 states in the United States since 1997 by conducting interviews with mothers and analyzing DNA obtained from cheek swabs from family members. That study includes both infants with 1 or more specified birth defects (diaphragmatic hernia, esophageal atresia, small intestinal atresia, anorectal atresia, neural tube defects, omphalocele, or limb deficiencies) and control infants without those birth defects.

For this study, the researchers analyzed data from a case group consisting of 2853 live births, stillbirths, or elective terminations with estimated dates of delivery from October 1, 1997, through December 31, 2005, and with 1 or more of the identified birth defects. The control group comprised 6726 infants born alive and without birth defects during the same period, randomly selected from birth hospital information or birth certificates.

Dr. Lin’s team concentrated on periconceptional use of anti-inflammatory medications, bronchodilators, or both. They defined exposure as use of asthma medication once or more from 1 month before conception through the third month of gestation. Mothers who described their medication use as only “as needed” and who could not provide an exact time frame for use were excluded from the study.  (This is a good study design to exclude these patients…doesn’t give you biased results for minimal exposure)

The study found a statistically significant association between isolated esophageal atresia and bronchodilator use only (adjusted odds ratio [aOR], 2.39; 95% confidence interval [CI], 1.23 – 4.66). The aORs for esophageal atresia and anti-inflammatory use only (aOR, 1.61; 95% CI, 0.69 – 3.76) and for use of both bronchodilators and anti-inflammatory medications (aOR, 2.93; 95% CI, 0.88 – 9.75) were elevated, but were not statistically significant.

There was a statistically significant increase in the risk for isolated anorectal atresia associated with anti-inflammatory use only (aOR, 2.12; 95% CI, 1.09 – 4.12).

Use of both bronchodilators and anti-inflammatory medications was associated with a statistically significant increase in the risk for isolated omphalocele (aOR, 4.13; 95% CI, 1.43 – 11.95).

The results are not all bad however.  The medications studied were not significantly associated with 6 other birth defects studied (neural tube defects, anencephaly, spina bifida, small intestinal atresia, limb deficiency, and diaphragmatic hernia).

The researchers performed a stratified analysis by time of medication use, using the periconceptional period and the period from the fourth through ninth month of gestation. The positive associations were found only in infants of women who took the medications during the periconceptional period, and not in infants whose mothers took the medications only in the fourth through ninth months of pregnancy. 

My comment—>by the time you know you’re pregnant, you’ve had the exposure!

The authors write that from 60% to 67% of mothers of infants with esophageal atresia, anorectal atresia, and omphalocele used bronchodilators during their entire pregnancy, although these data were not shown.

This is a key point–“With the interview information available for analysis, we were unable to distinguish between the effects of asthma and those of asthma medications; however, we did observe that mothers with possible indicators of uncontrolled asthma or severe asthma episodes (eg, use of multiple bronchodilators) were at higher risk for delivering a child with 1 of the defects studied than those who used 1 bronchodilator,” the authors write.

“When regular use of bronchodilators is required, an activated inflammatory process is implied; thus, use of bronchodilators throughout pregnancy might indicate that these mothers had frequent or ongoing inflammatory exacerbations during pregnancy,” they add.

Noting the importance of controlling asthma during pregnancy, the authors write, “The current clinical guidelines and specific recommendations for aggressive asthma management during pregnancy should remain unchanged.”

“Given the low baseline prevalence of these defects, if the observed association proved to be causal, the absolute risks of asthma medications on these rare defects would be small,” they conclude.

The study was supported by the Centers for Disease Control and Prevention. The authors have disclosed no relevant financial relationships.

Clinical Implications

  • Clinical guidelines recommend that women with asthma maintain asthma medication use during pregnancy.
  • In the current study, positive associations were observed for anorectal atresia, esophageal atresia, and omphalocele and maternal periconceptional use of asthma medications, but not for other birth defects studied.

You must want to know how to treat esophageal atresia?

What is the Best Method for Testing Allergy to Drugs?

I must have a drug allergy….what is the best method for testing?  Countless times I have reviewed skin biopsy results that state evidence of a drug allergy.  Obviously, this is not a very specific method of diagnosis, so what does work?  I’ll copy the entire abstract for you and make some comments below.  In the meantime, if you’re interested in what doctors learn about drug allergy, this is a lecture from University of Texas–Southwestern designed for allergy fellowship training.  It’s a little long unless you’re a doctor, but have at it!  And yes, I trained at Children’s Mercy Hospital with Dr. Portnoy. 

L.M. Heinzerling; D. Tomsitz; M.D. Anliker  The British Journal of Dermatology. 2012;166(1):107-114. 

Is Drug Allergy Less Prevalent than Previously Assumed?

Background Rashes are a frequent conundrum in clinical practice as they may be reactive, drug induced or disease specific. Identification of the culprit drug is important as re-exposure may be harmful or even life-threatening and unnecessary avoidance of ‘innocent’ drugs leads to limitations of treatment options.
Objective To objectify the cause of suspected cutaneous drug reactions in a large patient population.
Method Over 5 years (2006–10), 612 patients with suspected cutaneous drug reactions were evaluated. Histology was assessed. About 200 patients were invited for complete work-up with skin tests (prick/intracutaneous testing and scratch/patch as indicated) and, if necessary, lymphocyte transformation tests (LTT). In special cases, drug provocation tests were conducted.
Results A total number of 141 cases with suspected drug reaction underwent full work-up (age 6–86 years; 75% female, 25% male). In 107 cases (76%) a drug was identified whereas 34 (24%) were reactive rashes or had other causes. Mostly, cutaneous drug reactions were maculopapular rashes, urticaria/angio-oedema; less frequently, acute generalized exanthematous pustulosis, drug reaction with eosinophilia and systemic symptoms, systemic drug-related intertriginous and flexural exanthema, toxic epidermal necrolysis and fixed drug eruptions were present. Of all the cutaneous drug reactions investigated, 39·8% were caused by antibiotics, 21·2% by anti-inflammatories, 7·6% by contrast media and 31·4% by others (oral antidiabetics, antimycotics, antipsychotics, antiepileptics and others).
Conclusion Clinical assessment overestimates the role of drug allergies in cutaneous reactions. Assessment of suspected drug reactions can be greatly improved by thorough evaluation including dermatological and allergological work-up with skin testing and assays such as LTT.

Out of a total of 612 patients, 141 cases with suspected drug allergy were fully evaluated with allergy testing. Interestingly, out of the tested subjects with suspected drug reaction one-quarter could not be confirmed by objective testing, and skin changes were tracked to another trigger. This agrees with data from other studies which also found that not all the suspected drug reactions were finally confirmed.

Thus, depending on prescreening, the role of drugs in sudden exanthema is overestimated. In plain English, all of these  cases would have been FALSELY attributed as drug reactions had it not been for the testing and work-up.

However, only rigorous testing (and provocation) can rule out or confirm the drug reaction and finally identify the culprit drug. Interestingly, it was by means of a lymphocyte transformation test (LTT) that one-fifth of the cases were identified, which thus represents an important tool shown to have a sensitivity of 78%, even though this methodology is often considered experimental.

Further studies are needed to specify the sensitivity and specificity of LTT in comparison with skin tests for each substance.

Pollens are bad out there, but when to test?

Allergy tests should be used only to confirm a diagnosis that has already been made on the basis of symptoms and medical history, advise 2 leading allergists in an article published in the January issue of Pediatrics.

Scott Sicherer, MD, from Mount Sinai Hospital in New York City, and Robert Wood, MD, from the Johns Hopkins Children’s Center in Baltimore, Maryland, reviewed the benefits and limitations of blood tests and skin-prick tests in the detection of allergic diseases.

Both the skin-prick test (SPT) and sigE test detect a sensitized state. “However, detection of sensitization to an allergen is not equivalent to a clinical diagnosis. In fact, many children with positive tests have no clinical illness when exposed to the allergen,” Dr. Sicherer and Dr. Wood write.

They further point out that testing for allergens that do not make sense (because they would never be encountered in the patient’s environment or because the patient is obviously not allergic to them) could lead to “detrimental actions of unnecessary allergen avoidance.” They also warn against a false-negative on an SPT or sigE test when a child is obviously allergic to a particular trigger.

The allergists identify circumstances in which SPT and sigE are warranted:

  • To confirm a suspected allergic trigger after observing a child react
  • To monitor the course of a food allergy to detect when it might be waning or outgrown
  • To confirm allergy to an insect after an anaphylactic response, and to identify allergies to vaccines (SPT only).

SPT and sigE tests should not be used, Dr. Sicherer and Dr. Wood write, to screen for allergies in nonsymptomatic children or to diagnose food allergies or drug allergies. Food allergies should be assessed with food challenges, they write, and skin and blood tests do not detect antibodies to drugs.

The tests might be useful for identifying the trigger of a respiratory allergy (allergic asthma or seasonal or perennial allergic rhinitis) that is ubiquitous but not obvious in the patient’s environment: for example, SPT or sigE can detect allergy to dust mites, animal dander, cockroaches, molds, or pollen.

Pediatrics. 2012;129:193-97.

Are we harming ourselves?

“I’m allergic to everything!”  Ah, you’re smiling.  Is this really possible to be allergic to multiple drugs?  Evidently this is true according to a recent study published in Ann Allergy Asthma Immunol 108 (2012) 88–93.

Multiple drug intolerance syndrome: prevalence, clinical characteristics, and management byEric Macy, MD and Ngoc J. Ho, PhD.

So what is this condition? Multiple drug intolerance syndrome (MDIS) is generally defined as intolerance to 3 or more unrelated medications.  This can be antibiotics, ibuprofen, or high blood pressure medication.  The problem with adverse drug reactions is that intolerances are typically recorded in the “allergy” field of the medical record. This makes doctors and patients alike worry about anaphylaxis with any accidental use.  Relax….most adverse drug reactions are not going to result in a severe reaction without warning.  The authors of this paper use the word “allergy” in quotes throughout this paper to remind us that most of the drug “allergy” reports in the medical record are not immunoglobulin (IgE)-mediated.  

Now don’t misunderstand, a true IgE-mediated allergy requires sensitization, and every systemic exposure in a sensitized individual can potentially result in anaphylaxis and death. But this is not the type of reaction we’re dealing with in this study.

If you have Multiple Drug Intolerance Syndrome, what can you do?

  1. Most individuals with a record of any drug “allergy” have only 1 implicated medication, and they simply avoid that drug or class of medication. Individuals with multiple drug “allergies” are a special case.
  2. Antibiotic overuse probably accounts for a significant proportion of the antibiotic “allergy” reported.  Not only should antibiotics be avoided to prevent resistance, but overuse of antibiotics contributes to MDIS.
  3. Challenge testing has typically shown tolerance to most medications in patients with MDIS. Schiavino et al performed 1,808 challenges on 480 patients, 84.4% female, most ages 40 to 60, with histories of ADRs to at least 3 unrelated medications.
  4. All of these patients were evaluated at a specialized drug allergy clinic in Rome between January 1, 2000 and December 31, 2005. Two hundred twenty-four (12.4%) positive challenges were seen. In virtually all patients, either the index medication was tolerated on rechallenge or an acceptable alternative was identified.  

Multiple drug “allergy” is relatively uncommon in children, and most adverse drug reactions (ADRs) in children are associated with antibiotic use. Park et al provided demographic information on 97 children with 2 or more antibiotic “allergies” seen in a specialized drug allergy center in Canada. The accompanying editorial concluded that rare individuals may truly have allergic reactions to unrelated antibiotics, but it also might just be opportunity and bad luck.

 One often may stop multiple medications safely in the elderly. This may be the most important way to reduce the incidence of MDIS. In the presence of a life-threatening condition that would benefit from a particular medication associated with a historical reaction, based on a careful history, one may possibly safely test or rechallenge most individuals with MDIS.

 So is there anyone who should NOT be challenged with a drug they suspect is causing MDIS?

  • Individuals who have experienced drug-associated toxic epidermal necrolysis, Stevens-Johnson syndrome, blistering, desquamation.  These reactions are usually MORE severe after the second exposure! 

    example of Stevens Johnson syndrome

    Here’s what this type of reaction looks like:

  • Severe hepatitis, nephritis, or hemolytic anemia should not be rechallenged.  The risk of inducing severe reactions is just too great.  Fortunately, these severe reactions are rare.

  • Angiotensin-converting enzyme inhibitor–associated angioedema can be lethal, and rechallenge is not recommended.

If I have MDIS, when would a challenge be appropriate?

  • Urticaria or angioedema associated with NSAID use outside of aspirin-exacerbated respiratory disease is often transient, and rechallenge often can be safely performed.
  • Individuals with aspirin-exacerbated respiratory disease can be challenged with aspirin and desensitized.
  • Appropriate skin testing or in vitro IgE measurements can be used to evaluate individuals with MDIS who experienced classic IgE-mediated reactions such as anaphylaxis, shortness of breath, or hives. If negative, they can be rechallenged under observation.
  • If positive, they can be desensitized for 1 therapeutic course.
  • Multiple drug intolerance syndrome subjects with most other mild ADRs such as macular papular rashes, fixed drug eruptions, nausea, vomiting, gastrointestinal upset, diarrhea, drug fevers, other mild symptoms, or unknown symptoms can generally be safely rechallenged.

In closing, what’s the bottom line for patients with multiple drug “allergies?”

  1. Multiple drug intolerance syndrome may be considered partially an iatrogenic condition.
  2. Multiple drug intolerance syndrome is most prevalent in elderly women with high overall health care and pharmaceutical utilization.
  3. Multiple drug intolerance syndrome is associated with anxiety but not with life-threatening illnesses or IgE-mediated allergy.
  4. Coordinated efforts to reduce poly-pharmacy may be helpful in reducing iatrogenic MDIS.
  5. Drug hypersensitivity testing or drug challenges can be used safely to help manage many individuals with MDIS.

Call me with questions; I’d be happy to help you out!