allergic purpura Allergic purpura, also known as IgA vasculitis or Henoch-Schönlein syndrome, is a common vasculitic reaction. The body exhibits an allergic response to certain substances, leading to increased fragility and permeability of capillaries, resulting in inflammation and bleeding in the skin, joints, intestines, and small blood vessels in the kidneys. This condition is not infectious but does have a certain genetic predisposition.

Infection Factors

Bacteria: Mainly B-hemolytic streptococcus, with respiratory tract infections being the most common.

Viruses: Common in exanthematous viral infections such as measles, chickenpox, and rubella.

Others: Parasitic infections, mainly seen in roundworm infections.

Drug Factors

Antibiotics: Such as penicillin and cephalosporin antibiotics.

Antipyretic analgesics: Such as salicylic acid, prednisone, indomethacin, and quinine.

Other drugs: Such as sulfonamides, atropine, isoniazid, and thiazide diuretics.

Genetic Factors

Human leukocyte antigen (HLA) genes, familial Mediterranean fever genes, angiotensin-converting enzyme (ACE) genes, galectin gene, and vascular endothelial growth factor genes, etc.

Other Factors

Pollen, dust, vaccination, insect bites, and cold stimuli.

The classic tetrad of allergic purpura includes: skin purpura, joint symptoms, gastrointestinal symptoms, and kidney damage.

Skin Purpura

All patients exhibit varying degrees of purpura, mostly located on the limbs and buttocks, symmetrically on both sides. In children unable to walk due to the disease, rashes often appear on the face, trunk, and upper limbs.

In the initial stage, the rash is purplish-red papules, elevated above the skin surface, not fading upon pressure, and may be accompanied by itching but rarely pain. After several days, it turns dark purple, eventually becoming brown and fading, with a minority of severe patients developing large blisters. Generally, the rash fades on its own after 4 to 6 weeks, with some patients experiencing relapses at intervals of weeks to months.

Joint Symptoms

Most patients may experience joint symptoms, mainly swelling in the lower limb joints (knees, ankles, hips), which can also occur in the upper limb joints (hands, wrists, elbows), predominantly affecting single joints and restricting movement.

There is serous effusion in the joint cavity, generally without bleeding, and it can disappear within a few days without leaving any sequelae. Joint symptoms may appear before skin purpura but usually not exceeding 1 to 2 days.

Gastrointestinal Symptoms

About half of patients will experience gastrointestinal symptoms, mainly manifested as abdominal pain, mostly around the navel and lower abdomen, accompanied by nausea and vomiting. In severe cases, it can lead to gastrointestinal bleeding, intestinal ischemia, intestinal necrosis, intussusception, and intestinal perforation, although significant gastrointestinal bleeding is rare. Gastrointestinal symptoms may occur simultaneously with skin purpura, usually appearing within 8 days of the onset of skin purpura.

Kidney Damage

Some patients experience kidney damage, which is more common in older children and adults, mostly occurring within one month of onset, with varying severity.

Most patients exhibit hematuria, proteinuria, and urinary casts, accompanied by elevated blood pressure and edema, which can last for several months or even years, but most can fully recover, with a few progressing to chronic nephritis, ultimately leading to uremia.

Patients in the acute phase should rest in bed and avoid any physical activity. Actively identify and remove pathogenic factors.

Adopt a high-quality, low-protein diet and pay attention to vitamin supplementation.

In cases of severe gastrointestinal bleeding, fasting is necessary. For patients with positive occult blood in the stool but not severe abdominal pain, a liquid diet can be adopted.

If there is an infection, antibiotic treatment should be administered.

The traditional Chinese medicine treatment of allergic purpura includes the aspects of eliminating pathogenic factors and clearing the rash, addressing both symptoms and root causes.

The traditional Chinese medicine treatment of this disease lacks evidence-based medical support, but some traditional Chinese medicine treatments or medications can alleviate symptoms. It is recommended to seek treatment at regular medical institutions under the guidance of a doctor.

Patients: Strictly manage their lives and follow medical advice. Rest adequately, keep the skin clean, change into soft and clean underwear regularly, avoid using stimulating detergents such as soap to clean the skin, trim the nails in a timely manner, and enhance infection prevention.

Family members: Maintain household hygiene and cleanliness of bedding, regularly disinfect, help the patient stay away from allergens as much as possible, supervise the patient to take medication on time and as prescribed. Also, provide patients with patient and repeated psychological counseling, stabilize the patient's emotions, and reduce their anxiety and fear.

Rest: Patients with acute allergic purpura should absolutely rest in bed, and they should continue to keep warm and rest during the stable period, avoiding fatigue.

Diet: Gradually increase the variety of vegetables and fruits in the stable period, following the principle of "small amount, gradual increase, and stop when discomfort occurs".

Diet recommendations: Properly supplement fruits and vegetables rich in vitamin C, such as tomatoes, citrus fruits, etc., to protect blood vessels and prevent vessel rupture.

Diet taboos: Light diet, avoid spicy and irritating foods; within 2 months of the disappearance of skin purpura symptoms, avoid contact with and consumption of seafood, milk, eggs, and other potentially allergenic animal proteins; patients with positive proteinuria should restrict sodium intake.

Exercise: Any physical activity is prohibited during the acute phase of allergic purpura. After the condition stabilizes, appropriate exercise can be undertaken, following the principle of gradual and progressive intensity and time, avoiding strenuous exercise and prolonged standing.

If patients experience symptoms such as skin purpura, joint pain, and abdominal pain again after discharge, they should promptly seek medical attention.

Within 3 to 6 months after the disappearance of purpura and other symptoms, it is advisable to avoid receiving routine preventive vaccinations as much as possible. If vaccination against rabies is necessary, it should be done following medical advice.

Long-term avoidance of seafood, milk, eggs, and other potentially allergenic foods may not be conducive to the growth and development of children, so balanced nutrition should be supplemented.

Screen allergens as early as possible and stay away from potential allergens.

Prevent infections, actively control oral and ENT infections, and consider surgical removal in cases of recurrent tonsillitis.

Maintain regular daily routines, get adequate rest, avoid prolonged fatigue, emotional fluctuations, and mental stimulation.

Enhance physical exercise to improve the body's resistance.

Follow a light diet and consume less spicy and irritating foods.

Maintain personal and household hygiene and avoid mosquito bites.