Hello, Welcome to healthcare magic. I understand from your query that your sister is having psoriatic arthritis and you are look for treatment options for the same. Psoriatic arthritis could be quite debilitating if left untreated and requires prompt treatment. A drug which has got a good safety and efficacy record for psoriatic arthritis is Methotrexate. This has to be prescribed by a dermatologist/ rheumatologist and has to be monitored for side effects regularly. Other options include biological drugs which are a newer class like Infliximab. These are very expensive and also require regular monitoring for side effects. Shortness of breath and chest pain are usually not associated with psoriasis. If a patient has been on methotraxate, shortness of breath could indicate a side effect of methotrexate called as interstitial pneumonitis. Please check with your treating doctor about the possible treatment modalities I have discussed. Take care and I wish your sister good heath.