A 72-year-old woman with seronegative rheumatoid arthritis treated with leflunomide presented with a 6-month history of purple ulcerated papules and infiltrated red plaques on the dorsum of fingers and toes that appeared at the beginning of autumn. After topical treatment with steroids and antibiotics, the lesions improved but without complete resolution.
Physical examination revealed symmetrically distributed, non-infiltrated, pruriginous, and erythematous plaques on distal phalanges of fingers and toes. In addition, there were some red–purple papules over the knuckles of both hands (Fig. 1). There were no other skin lesions of concern, and she denied systemic symptoms. A complete blood cell count revealed marked leukopenia. Serologic tests were ordered, including autoantibodies, cryoglobulins, and complement. A punch biopsy specimen was obtained from a knuckle lesion and sent for histologic examination and direct immunofluorescence.
Histopathologic examination of the biopsy specimen demonstrated focal thinning of the epidermis with disappearance of interpapillary process (Fig. 2). There were some necrotic keratinocytes and basal vacuolar degeneration (Fig. 3). The superficial and middle dermis contained a perivascular lymphohistiocytic infiltrate. Findings from the direct immunofluorescence showed granular IgM deposition at the dermoepidermal junction consistent with our diagnosis of chilblain lupus.
Serologic test results showed an antinuclear factor titer of 1 : 160, positive findings for anti-Ro antibodies, and negative findings for anti-double-stranded DNA antibodies and cryoglobulins.
Chilblain lupus erythematosus.
Chilblain lupus erythematosus, which was first described by Hutchinson in 1888, is a relatively infrequent, chronic form of cutaneous lupus erythematosus. Most cases are sporadic and typically affect middle-aged women; however, a few familiar cases with autosomal dominant inheritance have been reported in childhood.
The lesions of chilblain lupus present as symmetrically distributed, sometimes infiltrated, pruriginous, erythematous or purple papules and plaques on the toes and fingers. The knees, elbows, ears, and nose are less often affected. The lesions, in their evolution, may ulcerate or present adherent hyperkeratosis. Generally, the first symptoms appear at the beginning of cold or damp periods and do not remit completely in the warm months as in “ordinary” chilblains.
In about half of all cases, the chilblain lesions develop many years after facial discoid lupus plaques, although they can occur at the same time as discoid lesions or in the absence of them. Chilblain lupus progresses to systemic lupus erythematosus in approximately 20% of all cases, especially those with typical symptoms of systemic lupus erythematosus. Therefore, it is indicated that patients should be evaluated for evidence of systemic involvement.
The histopathologic characteristics may include epidermal atrophy with follicular plugging and necrotic keratinocytes. An important feature in favor of chilblain lupus is the basal layer vacuolation. A perivascular lymphocytic infiltrate with mild edema is typical, and it often extends into the deep dermis and subcutaneous adipose tissue. Lymphocytic vasculitis may be seen. Direct immunofluorescence demonstrates granular dermoepidermal deposits of IgM and/or IgG; C3 is less frequently present. Patients are usually Ro antibody-positive. In most cases, it is not possible to distinguish chilblain lupus from idiopathic chilblain perniosis if the diagnosis is only based on clinical and histological features.6 The presence of the fluorescent lupus band and positive serologic test for antinuclear antibodies support the diagnosis of chilblain lupus. Instead, intense edema in dermis goes in favor of idiopathic chilblains.
The treatment of this entity is complicated and is not standardized. The more recommended therapies are topical steroids and systemic calcium inhibitors, besides protection from cold. Antimalarial agents are not as efficient as in other forms of lupus.