Study estimates number of ichthyosis patients in US (2012)

Leonard Milstone, MD,emeritus professor of dermatology, Yale University, New Haven, CT

October 31, 2012

Leonard Milstone, MD

There are widely accepted incidence figures for the common forms of ichthyosis, ichthyosis vulgaris, and X-linked ichthyosis.  Until now, however, figures for the incidence of rarer, generally more severe forms of ichthyosis have been approximations.  Accurate figures for incidence of moderate to severe ichthyosis are important when advocating on behalf of those affected and when requesting funds from governmental or private, non-governmental agencies.

A new study published in the September 2012 issue of Archives of Dermatology by Dr. Leonard Milstone, of Yale University and Chair of our Medical and Scientific Advisory Board, shows that every year, in the United States alone, at least 200 babies are born with a moderate to severe form of ichthyosis.  Dr. Milstone, along with Kay Miller, Merle Haberman, and Jayna Dickens of Thomson-Reuters, found that the incidence of moderate to severe ichthyosis is 5-10 per 100,000 people in the United States.  This means that for every 100,000 babies born in the United States 5-10 will have moderate to severe ichthyosis.  If 4 million babies are born each year, this translates to 200-400 new cases of moderate to severe ichthyosis each year.

The group used three independent databases, two insurance databases, and one hospital discharge database for their study.  Every disease is assigned a number called an ICD-9-CM code.  Some diseases can be given multiple codes and some codes cover many diagnoses.  The ICD-9-CM code for ichthyosis is 757.1, and Milstone and colleagues reasoned that moderate to severe ichthyosis would be diagnosed at birth and would not easily be confused with other, milder forms of ichthyosis or related skin conditions.  The analysis captured the number of babies less than 1 year old who were discharged from the hospital or who appeared on an insurance claim and were given the 757.1 code.  They found that the calculated incidence of ichthyosis was rather consistent each year over the period 2001 to 2010.

The actual incidence of ichthyosis may be even higher, however.  The newly published rates do not reflect the much larger number of newborn babies affected with milder forms of ichthyosis such as ichthyosis vulgaris and X-linked ichthyosis.

FIRST’s ability to provide current information when advocating on behalf of those affected with ichthyosis requires accurate, up-to-date statistics.  Kudos to Dr. Milstone and his colleagues for this great work!


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