Sunday October 22, 2017

Articles:225


5

December 01

Anaphylaxis from Substances Applied to the Skin


  When trying to determine the cause of an anaphylactic reaction,
  physicians and patients generally consider substances that had been
  ingested or injected, but may fail to consider agents that had been
  applied to the skin. However, the systemic absorption of many
  topically applied substances is well known, and in fact is used as the
  drug delivery system of choice (via transdermal patches) for such
  items as nicotine, scopolamine, and hormone replacement therapy. It
  must therefore be remembered that any topical application that is
  capable of causing systemic absorption is also capable of provoking
  systemic IgE mediated allergy—and not just cell-mediated contact
  dermatitis.

  Anaphylaxis has been reported from the use of the antibiotic
  Bacitracin applied as an ointment. Anaphylaxis has also been
  documented following the application of the commonly used insect
  repellant “DEET” (Diethyl-meta-toluamide) to the skin. A
  fascinating case report titled “Alpine Slide Anaphylaxis”
  described individuals who anaphylaxed after going down a recreational
  slide to which pollen grains had electrostatically adhered, the pollen
  then having entered the patients through mildly abraded skin. And
  allergists are certainly aware of the potential of skin testing to
  cause systemic symptoms.

  In addition to its possible role in provoking acute allergic symptoms,
  the skin is becoming increasingly recognized as the likely initial
  source of some types of sensitization. Recent examples include the
  induction of IgE to alpha-gal induced by tick bites, with the
  alpha-gal subsequently causing reactions to ingested beef; and the
  evidence suggesting that the initial sensitization of children to
  peanuts may be the result of skin contact with peanut butter in the
  home, with oral exposure to peanuts, in contrast, being more likely to
  induce tolerance than sensitivity.

  The skin is the largest organ in the human body. It should be
  respected as a route of allergen delivery for both allergic
  sensitization and allergic provocation.


November 30

Nasal Polyps

Nasal polyps are abnormal grey, glistening masses filled with inflammatory material, which may form in the nasal cavity or paranasal sinuses. Polyps may be diagnosed clinically by their characteristic appearance on exam with a nasal speculum or rhinoscope. Polyps are also identifiable on CT examination. In adults, nasal polyps are frequently associated with chronic sinusitis, asthma, and aspirin sensitivity, in the syndrome of "aspirin-exacerbated respiratory disease" (AERD). Some patients have concomitant allergic rhinitis or allergic fungal sinusitis. In children, nasal polyps are most commonly associated with cystic fibrosis. 

Large or extensive polyps cause symptoms of nasal airway congestion or blockage, thick discharge, and anosmia. Surgery can offer temporary relief, although polyps tend to recur within a few months to years following this intervention alone. Continued medical management of the underlying etiology is therefore mandatory after surgery, including intranasal glucocorticoids, allergen immunotherapy (if applicable), antileukotriene therapy, and daily lavage of the sinuses. In patients with AERD, aspirin desensitization followed by long-term daily therapy may be an additional therapeutic option.


November 29

Chronic Nasal Sores

Chronic nasal sores can be caused by a variety of inflammatory and infectious etiologies. Frequent nose picking or rubbing may lead to chronic infection of the nasal mucosa with Staphylococcus aureus, with development of ulceration, bleeding, and pain. Immunosuppressed individuals may develop infections from other bacteria, including Pseudomonas aeruginosa, and opportunistic microbes and viruses. Herpes simplex virus 1 may affect any mucous membrane, including oral cavity, lips, and nasal mucosa. Mycobacteria (tuberculosis, leprosy), syphilis, rhinoscleroma, and fungal infections may rarely affect the nose, with resulting chronic nasal sores. Intranasal drug use such as cocaine can lead to chronic nasal sores, ulceration, and eventual septal perforation.

Treatment of nasal sores includes topical antibiotic ointments such as mupirocin and appropriate oral antibiotics for severe infections. A culture of the lesion may be helpful in directing antibiotic therapy. Helpful adjunctive therapies include saline irrigations, local nasal care with warm compresses, and avoidance of digital manipulation.


November 28

Microbiota in the Colon

The large intestine is a bioreactor in which the host uses bacteria to degrade indigestible leftovers. Bacteria produce valuable substances such as vitamins and short fatty acids by degrading waste products.

In humans, resorption in the large intestine is restricted mostly to water and electrolytes. Bacteria in the human colon are mainly responsible for the reduction of the fecal mass. Which bacterial species are responsible for these processes are not well known. However, a reasonable assumption is that the numerically predominant bacteria are indispensable for the biochemical processes that occur in the colon. Eubacterium rectale (Roseburia spp), Faecalibacterium prausnitzii, and Bacteroides groups comprise each 10 to 30 percent and cumulative 70 percent of the total microbiota in humans. All other bacterial groups are present only in subgroups of individuals or in parts of the colon.

Although the fecal flora is one of the most well characterized microbiota, many of the bacterial species inhabiting the large intestine are unknown. Strict anaerobic species predominate, although the diversity of bacteria is high and consists of about 3000 to 5000 species.


November 25

Rinkel Controversial Skin test

Although skin testing in allergy normal involves prick (scratch) and intradermal methods for evaluation of immunological status. The intradermal skin test includes both immediate (seconds and minutes) in order to assess an allergic status (IgE- mast Cell) while it can also be used to assess cell mediated function that is measured in 24-72 hours.

 

However, another form of intradermal allergy skin testing that is controversial is the skin end point titration (SET) that uses intradermal injection of allergens at increasing concentrations to measure allergic response. The test is performed using progressive dilutions of allergens and after 10 minutes, the injection site is measured to look for growth of wheal. If there is more than 2 millimeters of growth in 10 minutes then the SET is considered positive. And then a second injection at a higher concentration is given to confirm the response. The end point is the concentration of antigen that causes an increase in the size of the wheal followed by confirmatory whealing. If the wheal grows larger than 13 mm, then no further injection are given since this is considered a major reaction.

 

Serial end-point titration (SET) testing ”studies” were actually empiric observations of individual reports and published as only case reports. There were no controlled objective assessments to support a specific claim for safety and efficacy (effectiveness in the real world). A critical

fault of this method is the lack of attention to the presence of erythema at the test site which would have been a prerequisite for

a specific diagnostic test of allergies in these diseases. Wheal diameter with accompanying erythema is an efficient indication of the degree of skin test reactivity to an allergen, but clearly if there was no erythema then it is likely to lead to clinically false-positive test results.

 

Thus the technique of skin testing by intradermal SET using the method of Rinkel is not recommended as a reliable test for IgE-mediated skin sensitivity due to

1:  because the tests are prematurely read during the course of the reaction, and the presence or absence of accompanying erythema is not considered;

2: the method clearly would generate additional and unnecessary intradermal injections;

3: the use of the  ‘endpoint’ as the dose for initiating immunotherapy frequently unnecessarily prolongs the course of treatment;

4: the ‘optimal’ dose of immunotherapy that is calculated is arbitrarily created;

5: and controlled studies show that it results in ineffective treatment.


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Location: Springfield, NJ
Today's Date: October 22, 2017
Station Director: Leonard Bielory, M.D
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