Curious yellow bumps on a baby’s heels

The Case

The parents of a healthy 12-month-old girl are worried about yellow bumps that have been present on the baby’s heels for 7 months. She was born at 34 weeks and spent 10 days in the neonatal intensive care unit (NICU). Since then she has grown and developed normally. WHAT'S YOUR DIAGNOSIS?

Dermcase diagnosis: calcified heel nodules

Heel nodules resulting in calcinosis cutis are caused by the pathological deposition of calcium phosphate in the skin.¹ Calcified heel nodules in infants have been linked to heel sticks since 1979.² These white or yellow papulonodular lesions typically appear at 4 to 12 months³; may be solitary or multiple⁴; and range from 1.5 mm to 5 mm in diameter.^1,5-9 The surrounding skin appears normal without erythema or other signs of inflammation.^3,4

Earlier reports have described these lesions as asymptomatic,³ but more recently there have been accounts of children presenting with nodules that were tender upon contact with footwear.^4,8,9

Lesions usually resolve without treatment by 18 to 30 months.³ The nodules often migrate to the surface and extrude through the epidermis.^1,3 However, sometimes the lesions may either recur or persist and there are cases that describe children presenting with these nodules at 4, 5, and even 7 years of age.^4,9

Epidemiology

The main risk factor for the development of these nodules is exposure to numerous heel sticks in the neonatal period.³ Babies at highest risk are usually premature; have a low birth weight; experience respiratory distress or other complications; and spend time in the NICU. However, several investigators also have described calcified heel nodules in full-term infants with uncomplicated birth histories,^5,6,8 one of whom developed a lesion after only 1 heel stick⁸ whereas others were pricked up to 8 times.⁶

There are not enough cases reported to reliably estimate the incidence or determine whether there is a gender or racial bias.

Etiology

There are 2 main theories that exist regarding the etiology of calcified heel nodules. Some researchers describe these lesions as dystrophic calcifications that occur secondary to trauma.⁴ Tissue damage induced by the heel stick causes the release of alkaline phosphatase, which increases pH and creates conditions that favor the precipitation of calcium phosphate. An alternate theory suggests that the nodules are calcified epidermal implantation cysts.⁷ Children with this condition have normal serum calcium and phosphate levels.^4,6

Differential diagnosis

Calcified heel nodules may resemble milia, staphylococcal pustulosis, and herpes simplex virus (HSV) infection. To diagnose this condition, a history of heel sticks with the typical clinical findings in a healthy child is usually sufficient.⁴ A radiograph may confirm calcification. Staphylococcal or HSV infection may be ruled out by Gram stain or Tzanck smear, respectively, as well as appropriate cultures, but these lesions would typically be painful and acute in onset. Whereas milia are common in newborns, they typically occur on the face and resolve within the first 2 to 4 months.

Treatment

Calcified heel nodules are usually self-limiting, so no treatment is needed¹ unless the lesions are tender and the child is in distress. There are no official guidelines on how to treat symptomatic nodules. Several methods have been described in case reports. In one case, removal by curettage with cauterization of the base led to a recurrence 5 months later, thus requiring subsequent deep curettage with local anesthetic to eliminate the lesion.⁴ In another case, removal by punch biopsy was more successful, with no recurrence reported in the 4-year follow-up period.⁷

Our patient

Because our patient's lesions were asymptomatic, reassurance was provided to the parents. The child will return for follow-up as needed. Interestingly, she has a monozygotic twin who had a similar NICU course but has not developed heel stick nodules. Although calcified heel nodules have been reported to occur in both monozygotic twins before,⁴ this is the first report of the lesions occurring in only 1 twin.

REFERENCES

1. Cambiaghi S, Restano L, Imondi D. Calcified nodule of the heel. Pediatr Dermatol. 1997;14(6):494.

2. O’Doherty N. Atlas of the Newborn, 2nd ed. Lancaster, UK: MTP Press; 1979:166.

3. Sell EJ, Hansen RC, Struck-Pierce S. Calcified nodules on the heel: a complication of neonatal intensive care. J Pediatr. 1980; 96(3 pt 1):473-475.

4. Williamson D, Holt PJ. Calcified cutaneous nodules on the heels of children: a complication of heel sticks as a neonate. Pediatr Dermatol. 2001;18(2):138-140.

5. Leung A. Calcification following heel sticks. J Pediatr. 1985;106(1):168.

6. Leung AK. Cutaneous nodule following heel pricks. Can Med Assoc J. 1985;132(10):1163.

7. Lemont H, Brady J. Infant heel nodules. Calcification of epidermal cysts. J Am Podiatr Med Assoc. 2002;92(2):112-113.

8. Rho NK, Youn SJ, Park HS, Kim WS, Lee ES. Calcified nodule on the heel of a child following a single heel stick in the neonatal period. Clin Exp Dermatol. 2003;28(5):502-503.

9. Braham SJ, Gilliam AE. Picture of the month: calcified nodule secondary to heel sticks. Arch Pediatr Adolesc Med. 2006;160(6):645. 

Ms Kryatova is a second-year medical student at Johns Hopkins University School of Medicine, Baltimore, Maryland. Dr Cohen, section editor for Dermcase, is professor of pediatrics and dermatology, Johns Hopkins University School of Medicine, Baltimore. The author and section editor have nothing to disclose in regard to affiliations with or financial interests in any organizations that may have an interest in any part of this article. Vignettes are based on real cases that have been modified to allow the author and section editor to focus on key teaching points. Images also may be edited or substituted for teaching purposes.