BACKGROUND: Morgellons disease is a controversial illness in which patients 
complain of stinging, burning, and biting sensations under the skin. Unusual 
subcutaneous fibers are the unique objective finding. The etiology of Morgellons 
disease is unknown, and diagnostic criteria have yet to be established. Our goal 
was to identify prevalent symptoms in patients with clinically confirmed 
subcutaneous fibers in order to develop a case definition for Morgellons 
disease.
METHODS: Patients with subcutaneous fibers observed on physical examination 
(designated as the fiber group) were evaluated using a data extraction tool that 
measured clinical and demographic characteristics. The prevalence of symptoms 
common to the fiber group was then compared with the prevalence of these 
symptoms in patients with Lyme disease and no complaints of skin fibers.
RESULTS: The fiber group consisted of 122 patients. Significant findings in this 
group were an association with tick-borne diseases and hypothyroidism, high 
numbers from two states (Texas and California), high prevalence in middle-aged 
Caucasian women, and an increased prevalence of smoking and substance abuse. 
Although depression was noted in 29% of the fiber patients, pre-existing 
delusional disease was not reported. After adjusting for nonspecific symptoms, 
the most common symptoms reported in the fiber group were: crawling sensations 
under the skin; spontaneously appearing, slow-healing lesions; hyperpigmented 
scars when lesions heal; intense pruritus; seed-like objects, black specks, or 
"fuzz balls" in lesions or on intact skin; fine, thread-like fibers of varying 
colors in lesions and intact skin; lesions containing thick, tough, translucent 
fibers that are highly resistant to extraction; and a sensation of something 
trying to penetrate the skin from the inside out.
CONCLUSIONS: This study of the largest clinical cohort reported to date provides 
the basis for an accurate and clinically useful case definition for Morgellons 
disease.