Tuesday, July 26, 2011

Can anaphylaxis return after leaving the ER?


Anaphylaxis is basically a severe allergic reaction. It may include rapidly developing hives, airway obstruction (wheezing or throat swelling), vomiting or diarrhea, drop in blood pressure, and/or loss of consciousness. People with severe food or bee allergies, for example, are at high risk for this type of reaction, and are generally advised to carry an adrenaline auto-injector for emergency use. This can be life saving, since early treatment will often reverse symptoms and allow enough time to get to a nearby hospital for further care.

However, about 11% of these reactions have a second phase occurring 1-20 hours after initial recovery (usually about 8 hours after the first reaction). It is important to be able to predict who is likely to have a second reaction, so that overnight in-hospital close observation can be arranged.

A return of symptoms is more likely if more than one adrenaline injection was needed at the beginning, or if there was a drop in blood pressure requiring IV fluid resuscitation. However, treatment with Benadryl or steroids (Prednisone or Medrol) does not change the likelihood of a second anaphylactic reaction.

Clin Exp Allergy 2009: 39: 1390-6. Clinical predictors for biphasic reactions in children presenting with anaphylaxis. Mehr S, Liew WK, Tey D, Tang ML.

Thursday, July 21, 2011

Why do nasal polyps form? What can we do about them? How do you know if they get worse or better?


Nasal polyps are often triggered by allergies to inhaled pollen or dust mites, animal danders, etc., but they also occur in non-allergic people, for example in cystic fibrosis, or in patients sensitive to aspirin. They are little benign sacs of eosinophil-filled fluid, which look a bit like grapes. They are silvery, translucent sacs often visible in the nasal passages. Polyps grow from a stalk based in a sinus, then grow outward toward the nasal passages and upon filling of this area, can cause obstruction of airflow to the olfactory nerves (therefore decreasing sense of smell), and often obstruction of the sinus openings, leading to chronic sinus infections.


Treatment: Debulking surgically is sometimes helpful temporarily, but there is a high rate of recurrence of polyps after surgical removal -- and it could be 20 yrs later, or 6 weeks later. So, we try to go with medical treatment and allergen avoidance first. The only medications that significantly shrink nasal polyps quickly are those containing a corticosteroid. Oral corticosteroids like Medrol or Prednisone can be very effective in reducing nasal polyps temporarily. However, to avoid long-term side effects, once the polyps shrink down, treatment can be switched to a topical nasal steroid spray indefinitely. You would likely be able to tell if your nasal polyps are recurring based on symptoms (severe nasal congestion or obstruction, loss of sense of smell, recurrent sinus infections). If allergies are present, allergen immunotherapy ("allergy shots") may help keep nasal polyps under control as well.


Monday, July 18, 2011

Probiotics may help childhood eczema


Probiotics such as Lactobacillus acidophilus, and Bifidobacterium lactis – otherwise known as “good bacteria” -- are readily available as a natural food supplement. In a recent study from the Ukraine, a group of 1-3 yr old children with eczema were given a mixture of these supplements twice a day for 8 weeks, and were compared with similar children not receiving probiotics. In the end, about 2/3 of the children in the probiotic treatment group improved significantly, while far fewer of the others improved. The probiotic group also needed less steroid creams to maintain control of the eczema, without any apparent adverse effects from the supplements. Therefore, it may be worthwhile to try probiotic supplementation, under the supervision of a physician, in children with severe eczema. Further studies are needed to confirm this finding.

Am J Clin Dermatol 2010; 11(5): 351-61. Probiotic Supplement Reduces Atopic Dermatitis in Preschool Children. Gerasimov SV, Vasjuta VV, Myhovych OO, Bondarchuk LI. (Dept of Pediatrics, Lviv National Medical University, Ukraine).

Friday, July 15, 2011

Is there a difference between having a milk allergy and being lactose intolerant?


Milk allergy and lactose intolerance are two completely different conditions, with very different potential risks as well as treatment. Food allergies occur when the immune system excessively produces a type of molecule called IgE, which specifically targets a particular food protein. Cow's milk contains several proteins to which IgE can be formed. Once "sensitized" by production of these IgE antibodies, ingestion of products containing cow's milk can produce a variety of allergic symptoms involving the skin (hives, swelling, itching), the respiratory tract (stuffy nose, coughing, wheezing), the gastrointestinal tract (abdominal pain, diarrhea, vomiting), or other systems -- and with repeated exposure to even tiny amounts, the reaction often worsens progressively and may culminate in full-blown anaphylaxis (the most severe of allergic reactions, which can be life-threatening).

Lactose intolerance, on the other hand, is the inability to digest the sugar portion of milk called lactose. This is caused by the lack of an enzyme called lactase, which is necessary in order to break down this sugar. This is a very common condition in adults, as well as in many children. Symptoms may be minimal when ingesting small amounts of lactose, but worsen with larger amounts. However, symptoms do not progress to more severe or widespread systemic reactions as seen with milk allergy. Persons with lactose intolerance can generally tolerate lactose-free milk, or any milk product if preceded by a lactase enzyme tablet available at most grocery stores and pharmacies.

Take home message: If you develop respiratory or skin symptoms in addition to intestinal symptoms after drinking milk, it may be dangerous to continue having milk products in your diet; stop until you can have allergy testing done to confirm whether milk allergy is the problem.

Monday, July 11, 2011

Can a child "grow out of" a peanut allergy?

Peanut allergies only resolve in about 20% of patients. Loss of sensitivity over time with strict avoidance is more likely to happen in patients with mild to moderate initial reactions, not as likely for those with severe skin or blood test evidence of peanut allergy, nor those with a history of anaphylactic reaction.


We generally track peanut IgE antibodies in the blood every 1-2 years initially to see if there is a downward trend. If you are one of the lucky 20%, and your blood test drops to minimally positive or completely negative, we will generally confirm this with a skin test. Only if both the skin test and the blood test are negative would we consider an oral peanut challenge. Then depending on how severe the initial reaction was, we may recommend doing the challenge in the office under observation with emergency medications and personnel nearby, rather than at home.

Friday, July 8, 2011

Looking out for latex allergy

Latex allergy has become more prevalent over the past 2 decades, with the increased use of latex gloves by health care providers as well as food handlers. But there are many other potential sources of latex in the environment, which can trigger allergic reactions in sensitized individuals, including the following:
  • balloons (except the mylar ones)
  • rubber "bouncy house" at children's parties
  • tires
  • exercise resistance bands
  • inflatable rafts (inner tubes)
  • latex gloves (dental/medical, hospitals; South Bay Allergy is latex-free)
  • tourniquets
  • IV ports (if hospitalized, notify hospital staff and your doctors that you are allergic to latex so they can take latex precautions)
  • some Ambu bags (used in resuscitation)
  • black rubber garden hoses
  • fresh asphalt (made with chopped up tires)
  • foam rubber (look out for foam mattress toppers or pillows, or latex pillow-top mattresses)
  • elastic (not usually a big problem unless there is direct prolonged contact with skin)
  • full-head rubber Halloween masks
  • some mouse pads (with rubbery underside)
  • some pencil erasers (the pink rubbery ones; the white ones are generally non-latex) -- can be a problem if used to erase writing, then the particles blown into the air toward the sensitive person
  • Koosh balls or rubber bouncy balls
  • restaurants where food preparers use latex gloves -- for example, if they make their own bread, often the cook will wear latex gloves while kneading the dough
  • dog toys (rubber Kong or other chew toys that are bouncy or flexible)
  • rubber soled shoes (usually not a big problem if only on the bottom, like tennis shoes, but watch out for flip-flops that are all rubber with direct skin contact)
This is not an exclusive list; check out our Resources link to the American Latex Allergy Association for more information.

Vitamin D deficiency may contribute to poor asthma control


Patients with asthma respond differently to inhaled “controller” medications, such as Asmanex, Flovent, Pulmicort, etc. Some patients require very small doses to achieve excellent asthma control, while others are more resistant to treatment. A recent study linked low Vitamin D levels to poor airflow rates through the bronchial tree, increased bronchial hyperreactivity (more “twitchiness” of the muscles around the bronchial tubes), and poor response to inhaled steroids.

So, while it is not yet proven, there is evidence that taking Vitamin D supplements may help improve treatment response as well as general asthma control. Your physician should approve all supplements, including Vitamin D, before starting treatment, and asthma controller medications should not be replaced with vitamins as the sole treatment for asthma.

Am J Respir Crit Care Med. 2010 Apr 1;181(7):699-704. Vitamin D levels, lung function, and steroid response in adult asthma. Sutherland ER, Goleva E, Jackson LP, Stevens AD, Leung DY (from Dept of Med and Peds at Natl Jewish Health in Denver, CO, and Dept of Med and Peds at Univ of Colorado, Denver).