Erythematous scaling lesions of the face, dorsal fingers, elbows, and knees together with symmetrical muscle weakness in a child

Abstract Juvenile dermatomyositis shows characteristic skin lesions. However, this does not rule out co‐occurring other autoimmune diseases, which may be more prominent regarding skin manifestations. Co‐occurring other skin autoimmune diseases should not be regarded as a preclusion for dermatomyositis. Here, we present an impressing case of juvenile dermatomyositis with co‐occurring psoriasis.


| CASE REPORT
We present a 5-year-old girl with a recent onset of erythematous and scaling lesions of the face, dorsal fingers, elbows and knees, cuticular hypertrophy, and periungual capillary dilatation (Figures 1,2). The patient also described a symmetrical pain and slowly increasing muscle weakness of her lower and upper extremities. After several days, muscle weakness worsened so that she was no longer able to walk upright, but instead started to crawl. Before onset of the disease, the patient showed a normal development. The mother reported that during pregnancy, she developed premature contractions in the 33rd week, and during that period, she was treated for gonorrhea with fluoroquinolones. There was no family history for any other diseases.
A 4-mm punch biopsy specimen of the skin of the left elbow was taken. The histopathological findings were typical for psoriasis ( Figure 3).
Based on the physical complaints, neurological status, muscle ultrasound of the thighs which showed an echorich activity of the muscles compatible with an inflammatory infiltration, laboratory testing (elevated creatine kinase levels [7.01 μkat/L, normal range <2/5 µkat/l]), lactate dehydrogenase levels (8.08 μkat/L, normal range <5.2 µkat/L), and a positive ANA titer of 1:2560, the diagnosis of dermatomyositis was made according to the European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) classification criteria for adult and juvenile idiopathic inflammatory myopathies. 1

| DISCUSSION
Juvenile dermatomyositis (JDM) is the most common myopathy in childhood. 2 It is a vasculopathy which is associated with proximal muscle weakness and characteristic skin manifestations such as microvascular dilation, Gottron's papules over extensor joint surfaces, and a heliotrope rash around the eyes. 2,3 The etiology of the disease remains unknown. Juvenile dermatomyositis may present as an amyopathic as well as a myopathic variant. 3 Characteristic features of JDM according to the latter survey are proximal muscle weakness (100%), arthralgia (55%), Gottron's papules (93%), heliotrope rash (87%), photosensitivity (55%), fatigue (82%), weight loss (40%), and abdominal pain (36%). 3 In clinically amyopathic JDM (CAJDM) myalgias, arthritis, contractures, calcinosis, dysphagia, abdominal pain, fatigue, and blood and serum abnormalities are less frequent. However, CAJDM and classic juvenile dermatomyositis (JDM) share a high percentage of positive ANA titers (70%-80%). 3 Psoriasis is not uncommon in childhood and can be associated with a positive family history. 4,5 It is characterized by erythematous papules and plaques with characteristic scaling. Both diseases, dermatomyositis and psoriasis, appear to share different signaling pathways of TNF-α and IFN-α/β signaling. 5 However, the role of IL-23-IL17axis signaling, which is of central importance in psoriasis, is still controversially discussed in dermatomyositis.
Interestingly, there are a small number of reports presenting both diseases in one patient at young age, similar to our case. 5 All three patients in the report by Nikki and co-authors were under the age of 18 and showed proximal muscle weakness and were treated with a combination therapy of methotrexate and methylprednisolone. In addition, one report demonstrates a patient at the age of 20 who had amyopathic juvenile dermatomyositis with psoriasis. 6 Current treatment options recommend the use of a steroid-pulse therapy with 30 mg/kg with a 1-g maximum dosage on several occasions in conjunction with oral administration of prednisone 0.5 mg/kg/d alone, or in combination with other immunosuppressants such as methotrexate. 5 If prednisone is given, a cushingoid body habitus and hypertrichosis may develop as side effects like in our patient (not shown). We added 15 mg/m 2 /wk methotrexate to reduce steroid dosage, as has been described elsewhere. 5 Due to a relatively safe profile, treatment options with TNF-α antagonists such as infliximab or etanercept may be used in children with treatment-resistant dermatomyositis. 7

ACKNOWLEDGMENTS
We confirm that there are no known conflicts of interest associated with this publication, and there has been no significant financial support for this work that could have influenced its outcome.

CONFLICT OF INTEREST
None declared.