Summary of case history,　The patient, male, was diagnosed with "recurrent nodular pain on the lower-limbs for 3 years and an ulcer on the right calf more than 1 month". Three years ago, it was found that dark erythema, nodules, patch, accompanied by pains were appeared on patient's lower-limbs with no obvious predisposing cause. Then, the patient was hospitalized several times with medical examinations on ANA, ENA, interferon-γ release assay (IGRA), Antibodies against neutrophils, Anticardiolipin antibodies (ACA), and all of results, however, were negative. In September 2022, the patient was treated due to diagnostic anti-tuberculosis for 6 months but with inefficacy for nudules. In September 18, 2022, we started to treat patient with Methylprednisolone, initially 8 tablets per day, then reduced to 4 tablets per day from April 2023, but with inefficacy. In March 2023, an ulcer was founded on the patient's right calf and the patient was hospitalized for ulcers but not healing. In initial diagnosis, it was found that edematous dark red spot and an ulcer which surfaced about 8cm*3cm and colored red with purulent secretion were appeared on the lower third of the right calf, accompanied tenderness around the an ulcer. In light of patient's pale face, emaciation and recurring an ulcer symptom, the patient was diagnosed with Qi and blood deficiency and was treated by invigorating qi and enriching the blood and promoting pus discharge and tissue regeneration for 7 days, and Methylprednisolone was reduced to 3 tablets per day, but the skin rash was not reduced. In further diagnosis, pains around an ulcer was more significant, the ulcer had not been alleviated. In light of patient's red and swollen with heat and pain in nodule, the ulcer wond was red and red tongue with yellowish greasy coating, the patient was diagnosed with damp-warm disease with syndrome of damp-heat and amassing poison and treated with Si-Miao Yong-An Tang along with the Si-Miao Pill to treat for 10 days with effect of clearing away heat and toxic materials, promoting diuresis, invigorating the blood circulation and relieving pain. As pains of nodule allevaiting and ulcer become shollowing, patient was treated as the different progression of the disease, also Methylprednisolone tablets reducing gradually and ending until June 14,th,2023. On June 18, 2023, the Methylprednisolone was discontinued, the ulcer was healed and the plaque on the lower-limbs subsided. In October 2023, the patient come to follow-up visit due to nodular masses of the lower extremities with recurrence of pain. And the patient's pulse and pathogenesis were basically the same as before, then patient was treated by Si Miao Yong An Tang alone with Si Miao Pill for 3 days, but with inefficacy. And the lumps of the lower extremities fuse into large areas with heats, nodules and lumps being more red with pain. Considering that interferon-γ release assay (IGRA) test was nagative again, the patient was diagnosed with dampness-heat toxicity accumulates in blood and treated with Si-Miao Yong-An Tang alone with Xi Jiao Di Huang Tang. After 5 doses, the heats were cooled and the pains in the lumps were subsided.,TCM diagnosis,　guatengchan (noxious damp-heat accumulated),Western medicine diagnosis,　nodular vasculitis,Therapeutic methods,　In early treatment, we took Si Miao Yong An Tang as main prescription, under the main syndrome differentiation points that red and swollen with heat and pain in nodule, the ulcer wond was red and red tongue with yellowish greasy coating. In the relapse phase, Xi Jiao Di Huang Tang was used to clear the heat in the blood. After the nodules and plaques subsided, patient was treated as the different progression of the disease with effect of curing heat and detoxification, promoting dampness and blood and dispersing stasis, accompanied by invigorating qi and supporting righteousness.,Clinical outcomes,　Hormones discontinued, an ulcer healing and nodules subsided