Table 2.
Laboratory features of digital dermatitis versus Morgellons disease
| Characteristic | Digital dermatitis | Morgellons disease |
|---|---|---|
| Detection of spirochetes in lesions | Treponema spp | None detected |
| Detection of coinfecting pathogens in lesions | Yes, many bacterial species | Polymerase chain reaction testing revealed no significant difference compared with controls |
| Presence of fibers or filaments | Keratin filaments/fibers reaching several centimeters described | Fibers/filaments up to several centimeters long and of unknown composition described |
| Positive serology to Borrelia burgdorferi | Positive serology reported, Treponema spp. shown to cross react with Borrelia burgdorferi antigens | Positive serology frequently reported (clinical Lyme diagnosis also frequently reported) |
| Positive serology for coinfecting pathogens | Not applicable | Frequently seropositive for various tick-borne pathogens |
| Histology of lesions | Said to resemble those of yaws, hyperplasia, acanthosis, and elongated keratinocytes observed that may be involved with filament production | Not well described, may bear a resemblance to yaws, hyperplasia reported. Fibers observed under and in skin, and piercing through skin. Fibers have been reported growing out of hair follicles |
| Changes to keratinized tissue other than skin | Hair loss in lesion, hypertrophic hair growth surrounding lesion, heel deformities, clubbed hooves, undercutting of hoof wall reported | Patients have reported changes to texture and feel of hair,25 deformity and loss of toe/fingernails reported49 |
| Fiber/filament composition | Keratin | Unknown, but cellulose proposed, possibly keratin (physical and histological properties consistent) |
| Color of fibers | Mostly white, gray or off-white | White, red, blue, purple, black (all possible colors seen in keratin) |
| Lesion location | Mostly heel bulbs on skin above the coronet band | Lesions anywhere, may indicate disseminated infection |
| Gross appearance of lesions | Early lesions are concave, painful; late, chronic lesions are convex, granulomatous with protruding filaments; healing lesions are hyperpigmented, dark gray rubbery scars | Concave, painful; fibers may protrude from skin lesion; may scab; healing tissue hyperpigmented |