Inclusion Criteria:

• Subject gives voluntary written informed consent to participate in the study.
• Diagnosis of systemic sclerosis (SSc) as defined by American College of Rheumatology (ACR) criteria.
• Males and females age greater than 18 years
• Presence of at least one active digital ulcer (meets protocol defined qualifications for active digital ulcer)
• Females of childbearing potential must be willing to use a reliable form of medically acceptable contraception and have a negative pregnancy test
• Able to communicate effectively with study personnel and willing to comply with protocol requirements.

Exclusion Criteria:

• Diagnosis of pulmonary arterial hypertension (PAH).
• Body weight less than 40 kg
• History of postural hypotension, unexplained syncope, a blood pressure that is less than 90 mmHg systolic or 50 mmHg diastolic at Screening and Baseline.
• Hemoglobin concentration less than 75% of the lower limit of the normal range
• Moderate to severe hepatic impairment, i.e., Child-Pugh Class B or C.
• Intractable diarrhea, or severe malabsorption, defined as greater than 15% unintentional loss of body weight in the last 6 months prior to Screening; any severe organ failure (e.g., lung, kidney), bleeding diathesis or platelet disorder, or any life-threatening condition.
• Pregnancy or breast-feeding.
• Overlap with another connective tissue disease that could affect rest pain and hand function (e.g. diabetes mellitus, rheumatoid arthritis).
• Sympathectomy of the upper limb performed within 12 months of Baseline. Sympathectomy performed on the non-target limb (hands not presenting with qualifying ulcers) or which did not include the hand performed within 6 months of Baseline.
• Receipt of prostanoid treatment (epoprostenol, treprostinil sodium, or other prostacyclin analog) within the previous 3 months of Baseline for conditions including Reynaud's phenomenon, rest pain and / or digital ulcers.
• Required systemic antibiotics for infected digital ulcers within 2 weeks of Screening.
• Local injection of botulinum toxin in an affected finger within 1 month prior to Baseline.
• Treatment with endothelin receptor antagonists within 1 month prior to Baseline.
• Patients on phosphodiasterase inhibitors, such as sildenafil, or tadalafil, who have received treatment for less than 6 months prior to Baseline (unless for intermittent treatment of male erectile dysfunction).
• Treatment with statin within 1 month prior to Screening, unless for management of hyperlipidemia.
• Received an investigational product within 1 month preceding Screening.
• Known hypersensitivity to treprostinil diethanolamine or any of the excipients.
• Tobacco use at any level within the past 6 months prior to Screening.