Polymyositis / Dermatomyositis

Polymyositis / Dermatomyositis General Information

Polymyositis / Dermatomyositis are two related conditions, characterized by the inflammation of the skin and the muscles of the affected patient – with the consideration that skin involvement is only present in the case of dermatomyositis. Their causes are unknown but it is suspected that they may occur as a result of viral infections or autoimmune reactions. In some cases, these affections have been coupled with other autoimmune diseases, such as scleroderma, lupus or vasculitis. These conditions may also appear as paraneoplastic phenomenon, which are an indication of the presence of cancer within the organism, and in such cases the affection will recede once the malignant tumors have been eliminated from the patient’s body.

Polymyositis / Dermatomyositis have been shown to have a larger rate of occurring in female patients, and incidence rate in black people seems to be of 5:1 when compared to patients of other races. The symptoms of the affections generally appear during the adult period, in patients older than 20 years of age, and they develop over prolonged time periods – it may take weeks or months for the disease to evolve and for the signs to become visible. However, cases of children with ages between 5 and 14 affected by these conditions have also been recorded. Both these conditions are fairly rare disorders, with an incidence rate of around 1 in 100,000 people per year. Although the mortality rate has been estimated around 20% within a 5 year period, in many cases it is associated with the underlying cancer or pulmonary complications.

Polymyositis / Dermatomyositis Symptoms

Patients diagnosed with Polymyositis / Dermatomyositis have been known to present skin rashes (only present in cases of dermatomyositis) and weakness of proximal muscles, which may or may not be accompanied by pain under the form of muscle cramps. The pain intensity may vary from mild to severe. The patients will generally experience difficulties when performing physical exercise, and in a case-by-case basis this may imply difficulty climbing stairs, standing up from a reclined or sitting position or performing more difficult physical tasks. Fatigue and discomfort may be present in Polymyositis / Dermatomyositis, and in such cases it is common that the patient also has low grade fever. In some cases, weight loss has been observed as well.

Also patients affected by Dermatomyositis may present a swelling of the area around the eyes. This may be accompanied by a discoloration of the area towards a violet hue, while the limb articulations (knees, elbows and knuckles) may present a reddish aspect, condition known under the name of Gottron's sign. The patient’s face, neck and torso may be covered by a reddish rash. Also, the patient may develop calcium deposits under the form of solid lumps in the skin, and especially in the fatty layers; this is a very common occurrence in patients with a childhood onset of Polymyositis / Dermatomyositis. Patients who also present complications in the cardiac or respiratory systems may also present symptoms specific to those affections. Arrhythmia, heart failure and / or shortness of breath have been reported in such cases.

Polymyositis / Dermatomyositis Treatment

The treatment of choice in treating Polymyositis / Dermatomyositis cases is the administration of corticosteroids in high doses, as they may have a strong positive effect in decreasing the inflammation in the muscles and skin of the patient. Available both as oral pills and IV solutions, these drugs may be prescribed for extended periods of time based on the periodic checkups and blood tests performed in order to establish the symptoms and general health condition of the patient.

There are many side effects associated with prolonged use of corticosteroid type drugs. Appetite and weight increase, as well as easy bruising and puffiness of the face have repeatedly been associated with this type of treatment, as well as increased sweats, stomach disorders, increased facial hair growth and swelling of the limbs. In some cases, acne, osteoporosis and cataracts have also occurred, while other patients experienced a worsening of an already existing case of diabetes. High blood pressure as well as an increase in the risk of infections are also common side effects associated with prolonged use of corticosteroids. Less often, avascular necrosis may occur – this consists of severe bone damage and it may completely destroy the large joints of the shoulders and the hips. Apart from that, it has been noted that abruptly ceasing corticosteroid treatment may result in recurring of the Polymyositis / Dermatomyositis as well as in another series of side effects such as vomiting, nausea and a drop in blood pressure.

In some cases, corticosteroid therapy does not yield the desired results, and immunosuppressive therapy is employed to treat the Polymyositis / Dermatomyositis. This class of drugs acts by inhibiting the immune system reaction causing the white cells to stop accumulating in the affected area, and examples of such drugs that may be prescribed in treating these affections are Methotrexate – available either as pills or injections - and Azathioprine, which is only available in oral form. Both of these may cause severe side effects involving bone marrow and liver tissue and the patient must be kept under monitoring for the entire course of the treatment. Other drugs, such as Chlorambucil, Cyclophosphamide and Cyclosporine have been used, especially in cases where the patient also presents serious complications of the affections such as pulmonary fibrosis. Resistant cases may also be treated with intravenous Immunoglobulin, as well as intravenous Rituximab.

In cases where the patient presents calcium deposits, the prescribing health care specialist may advise the use of Diltiazem in order to reduce the size of the deposits, but the effect may take years to occur and there is a limited effectiveness associated with this therapy. Also, physical therapy is typically prescribed for all patients affected by Polymyositis / Dermatomyositis. The exact therapy and exercises are prescribed on a case-by-case basis, as they may vary greatly according to the patient’s age, general health condition and medical history.

In order to obtain more information regarding the specific procedures and therapies employed in the treatment of Polymyositis / Dermatomyositis, patients are advised to consult with their personal health care specialists as they will be able to explain each treatment option in detail as well as advise the patient regarding which procedure and treatment plan is best suited to their case.