Dermatomyositis

Dermatomyositis (DM, also Lila disease) is an idiopathic myopathy ( = muscle disease ) or myositis ( muscle inflammation = ) with skin involvement and belongs to the group of collagen diseases. If only the muscles affected, it is called a rule of polymyositis (PM). Current studies on the pathogenesis of DM and PM are contradictory. There is not yet certain whether DM and PM have the same pathogenesis, in the following dermatomyositis is discussed separately and polymyositis is only referenced.

The disease is rare and can occur at any age. The frequency maximum is 50 years of age, women are more often affected than men ( Gynäkotropie 2:1). In children, age maximum is four to twelve years. In domestic dogs dermatomyositis occurs almost exclusively in puppies and young dogs.

• 2.1 clinic

Dermatomyositis of man

Paraneoplastic dermatomyositis

Approximately 50% of Dermatomyositiden associated with neoplasia. Works included ovarian carcinomas. It is therefore necessary to look at new-onset dermatomyositis by tumors. However, the temporal relationship to the onset of dermatomyositis to that of the tumor extremely variable - the skin and muscle disease may precede the tumor both, as well as follow or manifest the same time. In some cases, the recurrence of dermatomyositis after interim healing of a tumor whose recurrence, ie recurrence Show. Which occurs in the context of neoplasia dermatomyositis is completely reversible after removal of the neoplasia.

Juvenile dermatomyositis

The Juvenile DM presents itself as a multisystem disorder characterized by muscle weakness ( most proximal) and pain and typical lesions dar.

One cause is still unknown, but it is assumed that a virus autoimmunization ( esp. Coxsackie viruses are suspected ) is triggered by what it might be at times a vasculitis.

Clinic

• Muscle weakness ( always symmetrical, and mainly proximal, ie at the shoulder and pelvic muscles), muscle pain
• Lesions: Lesions: purple edematous erythema, va of the eyelids, face ( butterfly rash ) and the fuselage.
• Swelling and redness, and later atrophy of the skin can be found at the finger joint trek pages ( Gottron papules )
• Telangiectases on the fingernails

Diagnosis

The diagnosis is made based on clinical features described above. In addition, diagnostic of DM, elevated muscle enzymes ( creatine kinase ), transaminases and LDH. A muscle biopsy is necessary only in exceptional cases. In electromyogram it is often possible to demonstrate a myositis.

Therapy

Treatment consists of immunosuppression by

• Corticosteroids ( for example prednisolone)
• Cytostatic drugs (eg methotrexate)
• Immunosuppressants (eg, cyclosporine A)

In severe cases, a combination of the last two will be selected ( for example, methotrexate cyclosporine A) and in an early physiotherapy.

Dermatomyositis in dogs

In domestic dogs dermatomyositis occurs almost exclusively in puppies and young dogs (juvenile dermatomyositis ). Mainly affected breeds are collie, with a milder course also Sheltie and Australian Shepherd. A possible cause is due to the Breeds predisposed and within that also a family history, a genetic defect that leads to an autoimmune disease suspected. Also, the combination of the genetic defect with viruses is discussed.

Clinic

The disease usually begins after weaning at age 7-11 weeks. In mild forms of the early symptoms are often overlooked, so it is also noticed until 3-6 months.

Dermatomyositis is in the form of erythema, vesicles, pustules and crusts and not painful ulcers. These occur mainly on the face, tip of the tail and on the legs in the area of bony prominences. The lesions heal with scarring mostly from up to 8 months of age. The muscle symptoms usually appear only in the late stage, 1-2 months after the skin symptoms on. It comes to muscle weakness and wasting, where especially the chewing muscles are affected, so that food intake be greatly hindered and can salivation may occur.

The differential diagnosis must be excluded, especially lupus erythematosus, polymyositis and a leishmaniasis. The diagnosis can be made on histological examination of a Bioptats and electromyography.

While milder forms of dermatomyositis heal by itself in the middle forms a therapy with Pentofyllin can take place. Severe forms can be tackled with a combination of prednisolone and azathioprine, but the prognosis is poor, especially when it comes to pronounced muscle wasting. Traumas and sunlight should be avoided. Because of the familial clustering a breed recommended for exclusion.