ADHD, Skin Disease May Be Linked

March 25, 2003 (San Francisco) -- Babies and children who are prone to itchy, inflamed rashes -- a condition called eczema -- often suffer from sleeplessness and irritability. Worn-out parents and suffering children make frequent visits to pediatric offices seeking relief for this inflammatory skin condition, but new research suggests that it may be more than skin deep.

Typically, people with eczema also have asthma and other allergies, but it is the skin condition that can be most disruptive in young children. Anything from soap to the family pet can cause the skin to become extremely itchy and inflamed, causing redness, swelling, cracking, weeping, crusting, and scaling.

Now, a study of more than 43,000 children with eczema suggests that these kids are also at increased risk for a diagnosis of attention deficit disorder (ADHD).

Lead researcher Kristijan Kahler, MS, RPH, associate director of health economics and outcomes at Novartis Pharmaceuticals Corp. in East Hanover, N.J., tells WebMD that the new study doesn't conclude that eczema causes ADHD but it does point to a clear association.

But what is behind this observed association is still not clear. Kahler says, for example, that children with eczema are "up more nights and [are] more irritable than [children without eczema], and these children do make more physician visits, and these factors may contribute to increased diagnosis."

In fact, it was an observation by a Pennsylvania pediatric dermatologist, who happened to notice that several of his young eczema patients were also turning up with new ADHD diagnoses, that led Kahler and his colleagues to study the question.

They analyzed both medical records and prescription records from a pharmacy database to identify children with eczema in 1999. They then checked the medical and pharmacy records for these children in 2000 and 2001. Those records were compared with a group of "controls" -- children who were the same age and who had a similar number of doctors' visits, but who weren't diagnosed with eczema. The results were significant: 4.1 of the children with eczema went on to be diagnosed with ADHD, compared with 1.3% of the control group who had a subsequent ADHD diagnosis.

Moreover, the younger the child with eczema, the greater the increased risk for an ADHD diagnosis.

And the ADHDed diagnosis carries a significant economic impact: The cost of medical care for patients who are dually diagnosed can be almost twice as much.

Dermatologists attending the 61st Annual Meeting of the American Academy of Dermatology, where the new research was presented, were both intrigued and puzzled by the finding.

Alan B. Fleischer Jr., MD, professor and acting chairman of dermatology at Wake Forest University School of Medicine in Winston-Salem, N.C., says, "This is the single study that I was most curious about when we first received the poster abstracts. Clearly this is an observation that demonstrates some association, but what are we to make of this?"