Derm Case Mysterious rings on arms and legs

(RAMESH-THIS IS DERM CASE for CP)

THE CASE

You are called to the emergency room to examine a 3.5-year-old girl from Cameroon with several well-demarcated, indurated, and hyperpigmented plaques on the dorsum of her left hand and left lower leg and foot that have been slowly progressive for 4 weeks. The mother is quite anxious and seeks your input. She thinks it might be ringworm, but she is worried because there are so many lesions. The child’s history and the remainder of the physical examination are unremarkable.

DIAGNOSIS:

Granuloma annulare, localized type

CLINICAL FINDINGS

Granuloma annulare (GA) is a benign, self-limited, usually asymptomatic eruption most commonly occurring in children.^1,2 The primary skin lesions are usually round, annular, or serpiginous 1-cm to 5-cm nonscaling violaceous plaques with moderately indurated borders and central clearing or hyperpigmentation. Additionally, 1-mm to 2-mm papules may form an interrupted border and, rarely, may be present centrally.^2,3 The plaques are typically in a symmetrical distribution with a predilection for the distal extremities.³

GA presents in several subtypes: localized, generalized, subcutaneous, perforating, or patch. In localized GA-the subtype present in our patient-the dorsa of the hands and feet are the most commonly affected areas, but the ankles, legs, wrists, elbows, and even palms may also be involved.^3,4

EPIDEMIOLOGY

The epidemiology of GA has not been well studied. For localized GA, the onset is usually under the age of 30.² It is thought that GA affects mostly women, with the sex ratio most commonly reported as 2:1 or 2.5:1,^2,3 although some controversy does exist.⁴ There are also reports of multiple family members with GA, suggesting a possible genetic component.⁴

Associations between GA and the future development of diabetes mellitus, autoimmune thyroid disease, malignancies, drug allergies, hypertension, arthritis, and HIV/AIDS have been suggested or investigated.¹ However, none have been consistently or definitively proven.

HISTOLOGY

Although a biopsy is not usually required for diagnosis, if the decision to perform a biopsy is made, the most common pattern seen in localized GA is characteristic palisading lymphohistiocytic inflammation surrounding a central core of necrobiosis in the superficial and mid-dermis.⁵

TREATMENT

There are no randomized trials involving the treatment of GA.² Only case reports describing varying success with the use of topical or intralesional corticosteroids, interferon, vitamin E, retinoids, dapsone, chlorambucil, chloroquine, niacinamide, fumaric acid esters, pimecrolimus, tacrolimus, injection of sterile water, CO₂ laser, cryotherapy, radiotherapy, ultraviolet light, cryosurgery, and surgical excision have been reported in the literature.^2,4

Despite the paucity of evidence, treatment-particularly in children- is largely unnecessary because GA is usually asymptomatic and self-resolves in a few months to a few years.² Moreover, many of the treatments described may be painful and lead to scarring or atrophy.

DIFFERENTIAL DIAGNOSIS

GA is most commonly confused with tinea corporis,² as it was in our case. The most important differences to keep in mind are the presence of pruritus, scaling, and peripheral pustules in tinea corporis. If additional data is needed, a potassium hydroxide preparation and a fungal culture may be obtained and would only be positive in the case of tinea corporis. Contact dermatitis and nummular eczema as well as psoriasis and pityriasis rosea may also produce annular lesions, but like tinea corporis clinical findings include epidermal changes (eg, scale, lichenification, crusting), and psoriasis, contact dermatitis, and nummular eczema are associated with pruritus.

OUR PATIENT

We reassured the patient’s mother of the innocent course of granuloma annulare and scheduled them for a follow-up visit in 5 to 6 months.

References

1.    Barron DF, Cootauco MH, Cohen BA. Granuloma annulare. A clinical review. Lippincotts Prim Care Pract. 1997;1(1):33-39.

2.    Cyr PR. Diagnosis and management of granuloma annulare. Am Fam Physician. 2006;74(10):1729-1734.

3.    Friedman-Birnbaum R, Weltfriend S, Munichor M, Lichtig C. A comparative histopathologic study of generalized and localized granuloma annulare. Am J Dermatopathol. 1989;11(2):144-148.

4.    Martinón-Torres F, Martinón-Sánchez JM, Martinón-Sánchez F. Localized granuloma annulare in children: a review of 42 cases. Eur J Pediatr. 1999;158(10):866.

5.    Dabski K, Winkelmann RK. Generalized granuloma annulare: histopathology and immunopathology. Systematic review of 100 cases and comparison with localized granuloma annulare. J Am AcadDermatol. 1989;20(1):28-39.