• Patients with primary skin vasculitis, not associated with any significant extra-cutaneous involvement that would require specific immunosuppressive therapy. Eligible patients will have a diagnosis of either:

‣ Isolated cutaneous small vessel (SV) or medium-sized vessel (MV) vasculitis or cutaneous polyarteritis nodosa (PAN)

⁃ IgA vasculitis (IgA, formerly Henoch-Schönlein purpura), without active and/or progressing renal involvement (stable glomerular filtration rate (GFR) \>60 ml/min; absence of, or mild-and-stable microscopic hematuria without red blood cell casts; absence of, or mild-and-stable proteinuria (\<1g/24 hours); not requiring systemic immunosuppressive therapy).

• These conditions, when skin-limited, are all currently treated in similar manners in practice. Mild arthralgias, myalgias, peripheral limb edema, fatigue, weight loss ≤6 lbs or 3 kg within past 3 months, low-grade fever, and mild anemia (Hb ≥ 10 g/dL) will be allowed.

• The diagnosis of vasculitis must have been confirmed by skin biopsy prior to enrollment (earlier, at diagnosis, and/or just prior to enrollment) that has included an immunofluorescence study (in the case of small vessel vasculitis).

• Patients must have active cutaneous vasculitis lasting for at least 1 month continuously and/or have had 2 or more flares over the six months preceding enrollment (post-inflammatory lesions such as hyperpigmentation or healing ulceration(s) are not to be considered active vasculitis).

• Patients must have active / ongoing cutaneous vasculitis lesions at the time of enrollment (post-inflammatory lesions such as hyperpigmentation or healing ulceration(s) are not to be considered active vasculitis).

• Patients may have a contra-indication to one of the study drug or have been treated prior to enrollment with one of the study medications but failed to respond to it (according to the study definitions of failure and if they have been on the drug at the target dose or higher for 3 months or longer) or had to stop it because of an adverse event. Such patients can be enrolled directly in the second stage of the study and be randomized to receive one of the two other study drugs. The number of such patients enrolled directly in stage 2 will be capped at 10 (10% of the total recruitment target).

• Patients may have received systemic glucocorticoids for their cutaneous vasculitis before enrollment. For the patients on prednisone at the time of enrollment, prednisone should be stopped within a maximum of 6 weeks after enrollment and initiation of the study drug, following a pre-defined tapering schedule. Patients on long-term, low and stable dose of glucocorticoids (≤5 mg/day prednisone-equivalent) for other conditions (e.g., asthma or adrenal insufficiency) can be enrolled if the likelihood of requiring a dose increase for this other condition is low during the 6 month study period (these patients will remain on that low and stable dose during the study period, with the option to receive one short course of prednisone at higher doses for skin vasculitis flare during the first 3 months of the study period, like any other patients enrolled).

• Participant age 18 years or greater.