Allergic Purpura (IgA Vasculitis): Clinical Insights and TCM Syndrome‑Based Treatment

01 Revisiting the Nature of the Disease: A Century‑Long Medical "Re‑naming"

In the history of medicine, the naming of many diseases often lags behind the understanding of their true nature. Just as the whale — though called a "fish" and living its entire life in the sea — is now classified as a mammal because it breathes air, gives live birth, and nurses its young, so too has "allergic purpura" been misled by the term "allergic" for nearly a century, leading the public to mistake it for a common skin allergy.

In fact, allergic purpura is not the ordinary "allergic reaction" commonly understood by the public (i.e., the type I hypersensitivity mediated by IgE). Modern medicine has reached a consensus that its essence is a systemic small‑vessel vasculitis caused by the deposition of IgA immune complexes on the walls of small blood vessels throughout the body, in which the immune system attacks its own vessels. This conceptual shift — formalized by the 2012 international consensus conference, which officially renamed the condition IgA vasculitis — is the fundamental prerequisite for developing the correct treatment strategy.

If the disease progresses to the kidneys (i.e., "Henoch‑Schönlein purpura nephritis"), it may cause long‑term and even irreversible damage to renal function. Therefore, dispelling the "allergic" misconception and recognizing its true nature as a "vasculitis" is the first step toward accurate diagnosis and appropriate treatment.

02 Western Medicine: Clinical Manifestations and Classification

Based on the organs involved, the condition is generally classified into the following four clinical subtypes in Western medicine:

1. Simple cutaneous type

Manifestations: Symmetrically distributed purpura on the lower extremities (especially the extensor surfaces) and buttocks, with varying sizes and colors ranging from bright red to dark red or purplish red. The lesions may be raised above the skin surface and do not fade with pressure. Mild itching or pain may accompany the rash.

2. Articular (joint) type

Manifestations: In addition to purpura, there is swelling, pain, and even joint effusion in the joints — most commonly the large joints such as the knees and ankles — with restricted movement. The arthritis is usually transient and does not result in joint deformity.

3. Abdominal type

anifestations: Purpura accompanied by paroxysmal severe abdominal pain, typically localized around the umbilicus or the lower abdomen, and may be associated with nausea, vomiting, and bloody stools. Severe cases may lead to intussusception or intestinal perforation, which require close vigilance.

4. Renal type (Henoch‑Schönlein purpura nephritis)

Manifestations: This is the most severe subtype, characterized by hematuria, proteinuria, and casts in the urine, along with hypertension and edema. Renal involvement is the key determinant of long‑term prognosis, and a small proportion of cases may progress to renal insufficiency.

03 Western Medicine: Principles of Stratified Treatment

Simple cutaneous type: Mainly requires rest and supportive care, with adequate fluid intake. Routine use of glucocorticoids is not indicated. For patients with significant pruritus, short‑term oral antihistamines may be used to relieve discomfort; however, these medications do not control the underlying small‑vessel vasculitis.

Moderate‑to‑severe joint pain / abdominal pain: Oral glucocorticoids are the primary indication and can provide rapid symptom relief. It should be clearly noted, however, that corticosteroids do not prevent renal injury (2023 guidelines, Level 1B evidence).

Henoch‑Schönlein purpura nephritis: If moderate proteinuria or renal function impairment develops, renal biopsy should be performed. Treatment often requires combination therapy with immunosuppressive agents (such as mycophenolate mofetil or cyclophosphamide) or biological agents (such as rituximab).

04 Traditional Chinese Medicine: Syndrome Differentiation and Treatment

In traditional Chinese medicine, this condition falls under the categories of "grape purpura" and "Macular Toxin". Its pathogenesis is generally associated with heat‑toxin, blood stasis, and dual deficiency of qi and yin. In clinical practice, it is classified into the following main syndrome types:

1. Heat disturbing the blood‑collaterals (acute early stage)

• Key features: Often seen in the early phase, with newly appeared purpura that is bright red in color, accompanied by wind‑heat exterior manifestations such as fever, sore throat, and cough. The tongue margin and tip are red, with a thin yellow coating; pulse is floating and rapid.
• Pathogenesis: External wind‑heat attacks and disturbs the blood collaterals, causing blood to extravasate.
• Treatment principle: Disperse wind, clear heat, cool the blood, and calm the collaterals.
• Formula: Modified Yin Qiao San (Lonicera and Forsythia Powder).
• Reference for Western medicine correlation: Simple cutaneous type or infection‑triggered phase.

2. Blood heat causing reckless bleeding (acute fulminant stage)

• Key features: Sudden onset with dense, confluent purpura that is deep red or purplish‑black in color, possibly accompanied by epistaxis or hematochezia. High fever, thirst, and agitation. The tongue is deep red or crimson with a dry yellow coating; pulse is slippery and rapid.
• Pathogenesis: Intense heat‑toxin forces blood to rush recklessly, causing extravasation into the skin and internal organs.
• Treatment principle: Clear heat, remove toxin, cool the blood, and stop bleeding.
• Formula: Modified Xijiao Dihuang Tang (Rhinoceros Horn and Rehmannia Decoction), with buffalo horn substituted for rhinoceros horn in modern practice.
• Reference for Western medicine correlation: Acute severe phase (with high fever and gastrointestinal bleeding).

3. Damp‑heat obstructing the joints (articular type with mixed pattern)

• Key features: Purpura accompanied by red, swollen, hot, and painful knees and ankles, with restricted movement. The tongue coating is yellow and greasy; pulse is slippery and rapid.
• Treatment principle: Clear heat, resolve dampness, unblock the collaterals, and relieve pain.
• Formula: Modified Si Miao San (Four Wonders Powder) combined with Zhongjiao Xuanbi Tang.
• Reference for Western medicine correlation: Articular type.

4. Qi failing to control blood (recovery/prolonged stage)

• Key features: Recurrent purpura that is pale red in color and protracted, accompanied by fatigue, poor appetite, and a sallow complexion. The tongue is pale with a white coating; pulse is thready and weak.
• Pathogenesis: Prolonged illness consumes qi and blood, leading to the spleen's failure to control blood.
• Treatment principle: Strengthen the spleen, supplement qi, nourish blood, and consolidate blood.
• Formula: Modified Guipi Tang (Spleen‑Restoring Decoction) or Buzhong Yiqi Tang (Center‑Supplementing and Qi‑Boosting Decoction).
• Reference for Western medicine correlation: Recovery or protracted phase.

5. Yin deficiency with flaring fire (renal type / Henoch‑Schönlein purpura nephritis)

• Key features: Protracted purpura that may have subsided, with hematuria and proteinuria as the main features, accompanied by soreness and weakness of the lower back and knees, tidal fever and night sweats, heat in the palms, soles, and chest, dry mouth and throat, dizziness, and tinnitus. The tongue is red with scant coating; pulse is thready and rapid.
• Pathogenesis: Prolonged illness damages yin, giving rise to internal fire that burns the kidney collaterals, causing blood to extravasate into the lower burner.
• Treatment principle: Nourish yin, reduce fire, cool the blood, and stop bleeding.
• Formula: Modified Zhibai Dihuang Wan (Anemarrhena, Phellodendron, and Rehmannia Pill) or Dabuyin Wan (Great Yin‑Supplementing Pill).
• Reference for Western medicine correlation: Renal type (Henoch‑Schönlein purpura nephritis).

Supplementary note: In clinical practice, patients rarely present with a single pattern. Mixed patterns — such as blood heat with damp‑heat, or qi deficiency with yin deficiency — are common. Prescription adjustments should be made by a qualified TCM practitioner based on the patient's overall presentation.

05 Post‑Recovery Follow‑Up and Key Precautions

1. Renal monitoring is of paramount importance

• Urinalysis follow‑up: For the simple cutaneous type, a minimum of 6 months of follow‑up is recommended. If renal involvement has been present, follow‑up should be extended to 3–5 years.
• Morning urine testing is essential: It is recommended to consistently test the first morning urine sample, which yields the most accurate results. If eyelid edema or elevated blood pressure develops — even if urinalysis is normal — immediate follow‑up is required. In some cases, early kidney injury may manifest only as edema and abnormal blood pressure without significant findings on a single urinalysis; renal function tests should be performed to rule out underlying pathology.

2. Strictly avoid triggers (more important than blind dietary restriction)

• Primary trigger: Upper respiratory tract infections (colds, tonsillitis) are the most common triggers for recurrence and exacerbation, far more significant than food.
• Diet during the acute phase: When the rash is severe, only temporarily avoid spicy, irritating foods and alcohol, which may dilate blood vessels. There is no need for strict avoidance of all high‑protein foods (seafood, eggs, milk), as this may lead to malnutrition.

3. Physical activity management

• Acute phase: Absolute rest is required. Avoid prolonged standing or walking; elevate the lower limbs when resting to reduce gravity‑induced vascular stress.
• Recovery phase: After the rash subsides, gradually transition from slow walking to increased activity, but avoid vigorous running or jumping for at least 1 month.

4. Timing of integrated traditional Chinese and Western medicine

• During corticosteroid therapy: Avoid concurrent use of Chinese herbs that activate blood circulation and remove stasis (e.g., Salvia miltiorrhiza, Ligusticum chuanxiong), as they may increase bleeding risk. At this stage, TCM should focus on nourishing yin and reducing fire.
• During corticosteroid tapering: This is the optimal time to introduce spleen‑strengthening and qi‑supplementing therapies (such as Yupingfeng San), which can effectively reduce infection‑triggered recurrence.

5. Vaccine safety

• During the acute phase and within 3 months of stopping corticosteroids, live vaccines (such as MMR and varicella) are not recommended. Inactivated vaccines may be administered after the condition has stabilized, following consultation with a specialist.

06 Important Reminders

Important Notice: All traditional Chinese medicine formulas mentioned above are provided solely as illustrative examples of syndrome‑based treatment approaches. Individual patients vary significantly — in terms of age, constitution, concurrent corticosteroid use, and other factors — and it is strictly prohibited to use these formulas for self‑medication. All treatment and medication decisions must be made by a qualified TCM practitioner through an in‑person consultation, with regimens tailored to the individual patient.

Wu Chengshan – Associate Chief Physician (General TCM practitioner at Gansu Wuwei Cancer Hospital, with over 40 years of clinical experience. Recipient of the Jinchang City "Top Ten Youth" and "White‑Clad Angel" awards. Specializes in treating common disorders and most complex conditions of the five sense organs, respiratory system, digestive system, cardiovascular system, urinary system, rheumatic diseases, metabolic disorders, male and female reproductive health, dermatological conditions, and insomnia. Available for consultations every morning in TCM Clinic Room 305.)

Writer: Wu Chengshan, Xu Liping, Ye Hui

First Review: Yang Yang

Second Review: Guo Yishan

Third Review: Cai Qinghua

Wuwei Cancer Hospital, Gansu Province (Wuwei Institute of Medical Sciences)

（甘）医广【2025】第11-14-387号