Oral Health Group

Health Matters of Interest

March 1, 2004
by R.A.Clappison DDS, FRCD(C)


Toronto Western Hospital Krembil Neuroscience Centre researchers have discovered that low levels of a protein named “sonic hedgehog” may influence control of motion by the brain. “Sonic hedgehog” was named after a video game character. Originally it was thought that sonic hedgehog affected only the brain when it was developing but not the adult brain. Difficulty with walking, movement and co-ordination and shaking are the effects of this slowly progressing brain disorder.


Researchers gauged the electrical activity on slices of brain from adult rats without and with the addition of sonic hedgehog. The team discovered that the gene for sonic hedgehog is switched off in animals with an affliction similar to Parkinson’s disease. This discovery may lead to new medications that treat Parkinson’s disease by increasing the levels of sonic hedgehog in the brain.1


Occupationally-related contact dermatitis can develop from frequent and repeated use of hand hygiene products, exposure to chemicals and glove use. Contact dermatitis is defined as either irritant or allergic. irritant contact dermatitis is common, nonallergic, and develops as dry itchy irritated areas on the skin around the area of contact. By comparison, allergic contact dermatitis (Type IV hypersensitivity) can result from exposure to accelerators and other chemicals used in the manufacture of rubber gloves (e.g. natural rubber latex, nitrile, and neoprene), as well as other chemicals found in the dental practice setting (e.g. methacrylates and gluteraidehyde). Allergic contact dermatitis often manifests itself as a rash beginning hours after contact and. similar to irritant dermatitis, is usually confined to the area of contact.

Latex allergy (Type I allergy hypersensitivity to latex proteins) can be a more serious systemic allergic reaction, usually beginning within minutes of exposure but sometimes occurring hours later and producing varied symptoms. More common reactions include runny nose, sneezing, itchy eyes, scratchy throat, hives and itchy burning skin sensations. More severe symptoms include asthma marked by difficult breathing, coughing spells, and wheezing, cardiovascular and gastrointestinal ailments and in rare cases, anaphylaxis and death. The American Dental Association, (ADA) began investigating the prevalence of Type I latex hypersensitivity among dental health care professionals (DHCP) at the ADA annual meeting in 1994. In 1994 and 1995 approximately 2,000 dentists, hygienists and assistants volunteered for skin-prick testing. Data demonstrated that 6.2 percent of those tested were positive for Type I latex hypersensitivity. Data from the five subsequent years of this ongoing cross-sectional study indicated a decline in the prevalence from 8.5 percent to 4.3 percent. This downward trend is similar to that reported by other studies and might be related to latex gloves with lower allergen contact.

Taking thorough health histories for both patients and DHCP, followed by the avoidance of contact with potential allergens can minimize the possibility of adverse reactions. Certain common predisposing conditions for latex allergy include previous history of allergies, a history of spina abifida, urogenital anomalies, or allergies to avocados, kiwis, nuts or bananas.2


A presentation at the annual meeting American College of Allergy, Asthma and Immunology stated that Poinsettias contain two proteins similar to those found in rubber latex and these can cause a severe allergic reaction in those with latex allergy. Poinsettias are stated to be part of the same family tree as rubber latex.3OH

Dr. Clappison is Oral Health’s contributing consultant for Infection Control and Health Issues.


1.The Medical Posting, Macleans, Nov. 10/03.

2.Centres for Disease Control and Prevention, Guidelines for Infection Control in Dental Healthcare Settings – 2003, MMWR, 2003;52 (No. RR-17): 17,18.

3.Latex Allergy? Beware Poinsettias – Jeanie Larch Davis, American College of Allergy, Asthma and Immunology. WebMD in collaboration with The Cleveland Clinic ‘Latex Allergy.’

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