Dermatomyositis presenting as panniculitis
Authors: Chao Yen‐Yu , Yang Lih‐Jen 
Published: March 2003

A 44‐year‐old obese woman was transferred to our clinic with a diagnosis of panniculitis. Examination showed multiple, indurated, erythematous, painful nodules and plaques distributed on the shoulders, back, forechest, abdomen, buttock, and bilateral thighs. These skin lesions appeared 2 months previously, measured 5–8 cm, and were tender on palpation. No obvious inducing factor was traced. The lesions seemed unresponsive to treatment with nonsteroidal anti‐inflammatory drugs (ibuprofen, 400 mg three times a day) as similar lesions appeared in subsequent visits. Progressive proximal muscle weakness was found 1 month later. She was then admitted via the emergency room because of extensive painful skin plaques and abdominal pain. Diffuse erythematous to violaceous swelling of the face, neck, and shoulder was noted at about the same time ( Fig. 1). A skin biopsy specimen from the nodular lesion showed poikilomatous epidermal changes (
Fig. 2), and marked mononuclear cell infiltration in the dermis and subcutaneous fat (
Fig. 3). Dermatomyositis was considered as the diffuse violaceous facial erythema could be a form of heliotrope eruption, but Gottron’s papule was not found. At admission, serum creatinine phosphokinase (CPK) was mildly elevated (436 IU/L; normal range, 20–170 IU/L), but serum asparagine transaminase (AST) and lactate dehydrogenase (LDH) levels were within normal limits (36 IU/L; normal, 11–47 IU/L; and 108 IU/L; normal, 90–280 IU/L, respectively). Antinuclear antibody was 1 : 80 positive with an atypical speckled pattern. Muscle strength was weakest during the first 2 days, about grade 3 by the Medical Research Council (MRC) of Great Britain scale. Gower’s sign was positive. An electromyogram showed myopathic changes and a nerve conduction velocity study was normal. Serum enzymes were elevated further on the third day: AST, 55 IU/L; CPK, 783 IU/L with 100% MM form. The diagnosis of dermatomyositis was established. As for the work‐up result, anti‐dsDNA antibody, anti‐ENA antibody, and anti‐Jo1 antibody were negative. Tumor marker screen (β‐HCG, AFP, CEA, and CA‐125), was negative, and rhinolaryngopharyngoscope examination and gynecologic sonography were normal.Diffuse erythematous swelling with subtle violaceous hue extending from the temporal area to the cheeks, neck, and shoulders. The crusted lip ulcers of herpes simplex were also notedimageBasketweave hyperkeratosis, mild acanthosis, subtle vacuolar degeneration of the basal cells, and melanin incontinence (hematoxylin and eosin, ×400)imageHeavy mononuclear cells infiltrated in the subcutaneous fat tissue (hematoxylin and eosin, ×100)imagePancreatitis was initially suspected because of epigastric pain and tenderness, elevated serum lipase (382 U/L; normal, 23–200 U/L), and amylase (145 U/L; normal, 35–118 U/L). No evidence of pancreatitis could be found in abdominal sonography and abdominal computed tomography (CT), however. The epigastric pain and tenderness subsided soon after admission and the serum pancreatic enzyme level declined on the second day (amylase 69 U/L; lipase, 276 U/L).The patient was then diagnosed with dermatomyositis and treated with prednisolone (120 mg/day). CPK dropped dramatically from 3286 IU/L the day before treatment to 1197 IU/L 3 days after. Panniculitis lessened and the muscle power improved after 1 week of treatment.The disease activity fluctuated even with treatment with prednisolone and the patient often felt listless and weak. The muscle weakness sometimes deteriorated to affect the patient’s mobility. Facial erythema and panniculitis‐like lesions were found during the worse times. Methotrexate and azathioprine were then added (7.5 mg and 250 mg per week, respectively), but CPK was still mildly elevated (189 IU/L), and the patient still felt ill. Human immune globulin (5%, 500 mL per day, 5 days per month) intravenous infusion was initiated thereafter. There was a dramatic response. Full muscle strength was retained and CPK was within the normal range in the following 6 months with only immune globulin therapy.