Gastrointestinal disease

March 6, 2009

San Francisco - Because the human body is an ecosystem rather than a sterilizable object, an expert says that gastrointestinal flora play a key role in mediating cutaneous manifestations of a variety of gastrointestinal ailments.

San Francisco

- Because the human body is an ecosystem rather than a sterilizable object, an expert says that gastrointestinal flora play a key role in mediating cutaneous manifestations of a variety of gastrointestinal ailments.

"The average person carries 2 kg of microbes in their gut, and 200 g on their skin," says Magdalene Dohil, M.D., assistant professor of pediatrics and medicine, division of adolescent and pediatric dermatology, University California, San Diego, and Rady Children's Hospital, San Diego.

As such, she says that maintaining the integrity of the gut and skin requires preventing inappropriate immune reactions to these beneficial agents.


Hygiene hypothesis

The hygiene hypothesis suggests that preventing atopic dermatitis (AD) requires exposing children to potential allergens relatively early in life so their bodies will build appropriate defenses, she says.

It’s not just about eating dirt, Dr. Dohil says, but "eating the right dirt."

In younger children, AD’s symptoms include epigastric pain, nausea/vomiting and failure to thrive. Adolescents commonly experience eczema, allergic rhinitis and/or asthma, she says.

In epidermolysis bullosa, Dr. Dohil says, "Up to 60 percent of these children have significant gastrointestinal symptoms, such as difficulty swallowing."

Along with nutritional problems resulting from this inability, she says dermatologists also must keep in mind that these patients’ significant amounts of open skin cause them to lose proteins and fluids.


Newest player

The newest player in the atopic march (or progression from allergies to more significant atopies such as asthma) is eosinophilic esophagitis (EE), Dr. Dohil says. Its symptoms include mucosal pallor and thickening and stricture formation.

A recent review found that children under four years old more commonly experience patch test reactions to food, while older children typically react to inhalant allergies; however, only 27 percent of delayed responders to food proteins have positive skin tests (Pasha SF et al. Dis Esophagus. 2007; 20(4):311-9).

Accordingly, Dr. Dohil says dermatologists should consider EE in the diagnosis for any child with dysphagia, abdominal pain, vomiting, history of allergies and history of food impaction or stricture ’ particularly in school-aged males.

Going forward, she says that screening for the genetic marker eotaxin-3 might prove helpful in diagnosing AD.


Treatment

Regarding treatment, Dr. Dohil says that current evidence suggests probiotics are more effective in preventing rather than treating AD (Lee J, Seto D, Bielory L. J Clin Allergy Immunol. 2008 Jan;121(1):116-121). However, she says, probiotics in general remain controversial. DT

Disclosure:

Dr. Dohil reports no relevant financial interests.