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An infant with deviated great toenails
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A 2-month-old, full-term, healthy male presents to pediatric dermatology clinic for evaluation of his toenails. His mother reports that shortly after birth she noted erythema and edema of the lateral nail folds of both great toes. She denies any drainage. She applied topical antibiotic ointment for presumed paronychia twice daily for 7 days with minimal improvement. When inquiring about family history, you learn that the patient’s father had similar toenails in infancy.
On physical examination, the great toenails are both deviated toward the lateral aspect of the digit (toward the other toes) with surrounding, non-tender edema and erythema of both the medial and lateral nail folds. There is no exudate. The remainder of his toenails and all 10 fingernails appear normal.
Marissa J.
Perman
What is the most likely etiology?
Congenital malalignment of the great toenails
Congenital malalignment of the great toenails (CMGTN) is an uncommon condition in children, seen most often in infancy. As the name implies, children are usually born with this condition. Improvement with time is the natural course of the condition. The exact pathogenesis is not known, but there is thought to be a genetic predisposition.
CMGTN is usually observed by parents within the first several weeks of life due to changes in the tissue surrounding the nail plate. These changes include erythema, edema, paronychia and scaling. Over time, dystrophy of the nail plate may occur, including ridging, discoloration, thickening, and/or shortening. CMGTN can be unilateral or bilateral and is almost always associated with lateral rather than medial deviation of the nail plate.
The pathogenesis of CMGTN is unknown. One recent hypothesis suggests that the fetal development of the nail unit and the bone of the distal phalanx, usually closely coordinated in utero, become desynchronized. The nail unit then begins to develop more rapidly, leading to the lateral deviation observed at birth. CMGTN tends to improve over time, and according to the above hypothesis, may be explained by “catch up” growth of the distal phalanx with the nail unit.
Bilateral great toenails with lateral deviation and associated paronychia
of the right medial toenail fold.
Photo courtesy of Section of Dermatology, Children’s Hospital of Philadelphia
CMGTN is inherited in an autosomal dominant manner with variable penetrance. There are several reports of CMGTN in both mono- and dizygotic twins. In addition, CMGTN also has been reported in Rubinstein-Taybi syndrome and Naegeli-Franceschetti-Jadassohn syndrome.
CMGTN may be confused with onychomycosis because of discoloration and nail dystrophy. The history of these findings noted at birth or shortly thereafter, as well as a family history, should favor a diagnosis of CMGTN. If there is any question, a nail culture for dermatophyte or staining of a nail clipping with Gomori’s methenamine silver stain or periodic acid–Schiff (PAS) stain will help to distinguish the two entities. Other entities that may be considered include ingrown toenails, paronychia or congenital hypertrophy of the lateral nails folds of the hallux, all of which may present concomitantly with CMGTN.
In mild cases, reassurance is usually the most appropriate course of action, as improvement in the alignment may occur in the first several years of life. In the meantime, treatment for paronychia can be instituted when needed. In addition, keeping the nails short and horizontal may help prevent ingrown toenails. In more severe cases, surgical realignment before the age of 2 years has been recommended.
References:
Cohen PR. Pediatr Dermatol. 1991;8:43-45.
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