Infant with swollen fingers

October 1, 2010

A 4-month-old girl is brought to your office by nervous parents who point out swelling of all the fingers of her right hand associated with tender, deep nodules on the proximal and middle phalanges.

The Case

Diagnosis: Cold panniculitis

Cold panniculitis, sometimes referred to as Haxthausen's disease, is a benign condition resulting from cold injury and subsequent inflammation of the subcutaneous fat. It is most common in infants and small children,1 but adolescent girls and women appear to have a predisposition to it as well.2

The injury occurs most frequently on the cheeks (where it is often referred to as "popsicle panniculitis," after the commonly implicated inciting agent)1; however, it also can develop on the trunk and extremities.3

Cold panniculitis most commonly manifests as circumscribed, firm, erythematous, subcutaneous nodules.4 The nodules of cold panniculitis can be very tender and associated with edema of the surrounding tissues, as in our patient (Figure). It is very rare for ulceration, atrophy, or scarring to occur. In the related entity of fat necrosis of the newborn, the skin lesions can result in transient depression of the skin surface and occasional ulceration.3

Children are most prone to cold panniculitis because of their higher ratio of saturated to unsaturated fatty acids than adults, which contributes to higher melting and solidification points.3-5 Fluctuations in blood flow that occur with declining temperatures, ice crystal formation, and changes occurring with thawing also contribute to subcutaneous inflammation.6 In affected persons, cold exposure leads to crystallization and rupture of fat cells, and the resultant inflammation leads to persistent, indurated, erythematous nodules and plaques.3,5

DIFFERENTIAL DIAGNOSIS

Infants in particular are predisposed to 3 major forms of panniculitis: subcutaneous fat necrosis of the newborn, sclerema neonatorum, and cold panniculitis.5

In addition to cold, other extrinsic factors can lead to panniculitis. Sclerosing lipogranuloma (injected foreign lipid material), other injectable substances, and blunt trauma all can lead to similar clinical findings.6

It is important to distinguish cold panniculitis from subcutaneous fat necrosis of the newborn. Cold panniculitis is usually self-limited. Although not usually necessary to establish the diagnosis in clear-cut cases, a biopsy can be useful in distinguishing cold panniculitis from subcutaneous fat necrosis because needle-shaped clefts in lipocytes typically seen in the latter are absent in the former.6,7 The distinction is important because of the prolonged calcium monitoring required in cases of subcutaneous fat necrosis of the newborn.4 The morphologic appearance of cold panniculitis may lead some practitioners to confuse it with bacterial cellulitis.

PATHOLOGY

Sections reveal a predominantly lobular panniculitis, although some septal inflammation may be present. There are lymphocytic and histiocytic infiltrates and superficial and deep perivascular dermal infiltrates without vasculitis.4 The dermal-subcutaneous border and periadnexal regions are the most severely involved. Other microscopic features that may be present include neutrophils, poorly developed granulomas, mucin, adipocyte necrosis, and microcysts.6,7

TREATMENT

There is no specific treatment for cold-induced panniculitis other than the obvious removal and continued avoidance of the inciting agent. The lesions can be expected to resolve over the course of weeks to months. If present, hyperpigmentation can take much longer to resolve and may persist indefinitely to some degree.7 Our patient's lesions improved in 2 months.

MR SCHNEIDER is a fourth-year medical student at Johns Hopkins School of Medicine, Baltimore, Maryland. DR COHEN, the section editor for Dermatology: What's Your Dx?, is director, Pediatric Dermatology and Cutaneous Laser Center, and associate professor of pediatrics and dermatology, Johns Hopkins University School of Medicine, Baltimore. The authors and section editor have nothing to disclose regarding affiliation with, or financial interest in, any organization 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 editor to focus on key teaching points. Images may also be edited or substituted for teaching purposes.

REFERENCES

1. Rajkumar SV, Laude TA, Russo RM, Gururaj VJ. Popsicle panniculitis of the cheeks. A diagnostic entity caused by sucking on cold objects. Clin Pediatr. 1976;15(7):619-621.

2. Braverman IM. Skin Signs of Systemic Disease. 3rd ed. Philadelphia, PA: WB Saunders; 1998.

3. Cohen BA. Pediatric Dermatology. 2nd ed. London: Mosby; 1999.

4. Polcari IC, Stein SL. Panniculitis in childhood. Dermatol Ther. 2010;23(4):356-367.

5. Silverman AK, Michels EH, Rasmussen JE. Subcutaneous fat necrosis in an infant, occurring after hypothermic cardiac surgery. Case report and analysis of etiologic factors. J Am Acad Dermatol. 1986;15(2 pt 2):331-336.

6. Bolognia JL, Jorizzu JL, Rapini RP. Dermatology. 2nd ed. London: Mosby; 2007.

7. Quesada-Cortés A, Campos-Muñoz L, Diaz-Diaz RM, Casado-Jiménez M. Cold panniculitis. Dermatol Clin. 2008;26(4):485-489.