Skin infection masquerading as lupus erythematosous profundus

ARTICLE

Auteur(s) : Chrisoula Pipili¹, Evangelos Cholongitas¹, Elpida Giannikaki², Despina Ioannidou³

¹Department of Internal Medicine, General Hospital of Sitia, GR-72300, Greece
²Department of Pathology, General Hospital of Sitia, GR-72300, Greece
³Division of Dermatology, General Hospital of Sitia, GR-72300, Greece

A 55-year-old woman was admitted to our department with low grade fever and an erytho-violaceous, sharply demarcated plaque on her lower limb of 8 weeks’ duration. Firstly, it had been diagnosed as cellulitis and she received antibiotic treatment ampicillin/clavulanic acid, 625 mg per os tid for 7 days, without any improvement. Her medical history was unremarkable for other illnesses and medications. On admission she was febrile (37.5 °C) and she could not relate her cutaneous lesion with any specific presumptive cause (animal, insect bite or trauma). Physical examination showed a painful, solitary, erythematous, indurate and warm plaque of about 8-9 cm diameter on the inner surface of her left thigh (figure 1). Abnormal laboratory results included: Hematocrit: 36.6%, WBC: 14.150/mm³, C-reactive protein: 120 mg/L (upper normal levels: < 10 mg/L), Erythrocyte sedimentation rate (ESR): 47 mmL^th. She was started on a broader antibiotic (piperacillin/tazobactam (Tazocin) 4.5 gr qid) and a skin biopsy and further laboratory evaluations were performed. Serological investigations for hepatitis B and C, cytomegalovirus, herpes simplex viruses, HIV, toxoplasma gondii, mycoplasma and Borrelia burgdorferi were all within normal limits. However, autoantibody examinations were positive for antinuclear (ANA: 1/160, speckled fluorescence) and anti-Ro (SSA) antibodies (86.1 IU/mL, upper limit of normal < 6 IU/mL). Histopathological examination revealed periadnexal and perivascular inflammatory infiltrates (at all dermal levels and in septa of the fat in the subcutis) extended into the fat lobules, spotty adipocyte necrosis and fibrosis (features of panniculitis) and minimal vasuolar changes in the basal layer of the epidermis. All these histological features were consistent with lupus erythematosus profundus (LEP) (figure 2). Moreover, cultures of the biopsy specimens yielded no bacteria, acid fast bacilli, or fungi. Therefore, the diagnosis of LEP was established and the patient was started firstly on hydroxychloroquine, which was discontinued due to gastrointestinal upset and ultimately on prednisolone 1 mg/kg/day. Within the next days, the patient’s cutaneus lesion started to improve. She was discharged, afebrile with a slightly reduced skin lesion (6.5 cm), after 10 days. Corticosteroid treatment was tapered in small doses and the skin lesion resolved after 2 months. One year later, she remains on low dose prednisolone (10 mg/day), without any sign of LEP recurrence (ANA: 1:12), but with scar centers on the previous lesion site.

LEP is a rare manifestation of cutaneous lupus erythematosus occurring in about 1-3% of cases [1, 2]. The deep dermis and the subcutaneous fat are usually involved in a chronic and recurrent clinical course [1, 3]. Although it may occur in patients with known discoid or systemic lupus erythematosus (SEL) or, as in our case, as isolated entity, it is estimated that only 10-12% of LEP progresses to SEL after a long follow up period [4]. LEP is characterized by deep dermal plaques or/and subcutaneous sharply defined non-tender nodules, usually localized on the head, face, upper dermis and rarely, as in our case, only on the inner surface of the thighs [5]. Another exceptional feature of our patient was the typical sign of microbial infection which was ultimately masquerading as the presence of LEP. Its differential diagnosis may be difficult, due to the lack of well-defined diagnostic criteria and the similar histopathological findings with other clinical conditions, such as T-cell lymphoma [6].

To our knowledge, our case constitutes a rarity of LEP, and is the first report where the clinical (painful, erythematous, warm plaque with fever) and the biochemical (moderate elevation of CRP) signs were suggestive of microbial cellulitis. Although these findings cannot fully be explained, it is possible that previously unrecognized topical microbial infection triggered autoimmune mechanisms leading to the development of LEP. Fortunately, the poor response to intial antibiotic treatment was helpful for deciding for further evaluation with autoantibodies and skin biopsy immediately after the patient’s admission.

Acknowledgements

References

2 Suda T, Hara H, Okada T, Suzuki H. Coexistence of extensive calcification and membrano-cystic changes in lupus erythematosus panniculitis associated with systemic lupus erythematosus. Eur J Dermatol 2007; 17: 86-8.

3 Biswas A, Byrne JP. Extensive endarteritis obliterans in a case of lupus panniculitis with membranocystic changes and dystrophic calcification: a pathogenetic link? Eur J Dermatol 2007; 17: 550-1.

4 Martens PB, Moder KG, Ahmed I. Lupus panniculitis: clinical perspectives from a case series. J Rheumatol 1999; 26: 68-72.

5 Ng PP, Tan SH, Tan T. Lupus erythematosus panniculitis: a clinicopathologic study. Int J Dermatol 2002; 41: 488-90.

6 Massone C, Kodama K, Salmhofer W, Abe R, Shimizu H, Parodi A, Kerl H, Cerroni L. Lupus erythematosus panniculitis (lupus profundus): clinical, histopathological, and molecular analysis of nine cases. J Cutan Pathol 2005; 32: 396-404.