Pustular vasculitis: causes, symptoms, diagnosis, and treatment

There are many aseptic pustules in dermatology, but there are few vasculitis with neutrophil infiltration in the dermis under the pustules. Pustular vasculitis is a group of disorders with histopathological manifestations of intraepithelial spongy pustules, acute febrile neutrophilic dermatosis-like vascular reactions in the dermis under the pustules, with vascular neutrophil infiltration, leukocytoclasis, and hemorrhage, without fibrinoid deposition in the vascular wall, with leukocytoclastic vasculitis-like manifestations, probably with microabscess or neutrophilic dermatosis, including bowel arthritis dermatosis syndrome, Behcet's disease, acute generalized pustular bacterid, IgA-associated vasculitis, Reiter's disease, and pustular vasculitis or pustular drug reactions after BCG vaccination.


Causes

The disease is a vasculitis caused by immune complexes, and aseptic pustules may be caused by a certain factor causing neutrophil chemotaxis. Neutrophil chemotactic factors produced in the epidermis attract neutrophils to aggregate in the epidermis, resulting in aseptic pustules. It is believed that neutrophil chemotaxis is a percutaneous discharge mechanism of elimination of immune complexes.


Signs and Symptoms

Aseptic pustules occur on the basis of erythema or purpura, usually in a group of reactive skin disorders, often accompanied by systemic symptoms.

Pustular vasculitis occurs in these diseases:

Acute generalized pustular bacterid

The disease often occurs suddenly, initially in the palms and soles, soon spreading throughout the whole body, predominantly in the extremities. Aseptic pustules can be 8mm in diameter, spontaneously subsiding in 1 - 4 weeks, without recurrence tendency.

Behcet's disease

An important skin symptom of this disease is the formation of pustules and mild vasculitis within 24 hours after skin trauma. Immune complexes can be detected in the blood of patients. The immune complexes damaging the blood vessel walls and some unknown factors in serum leading to neutrophil chemotaxis are the cause of the disease.

Bowel-associated dermatosis-arthritis syndrome (BADAS)

Bowel-associated dermatosis-arthritis syndrome, also known as blind loop syndrome, bowel bypass syndrome, or intestinal bypass arthritis-dermatitis syndrome, is a serum sickness associated with bacterial overgrowth in the intestine, pustular vasculitis lesions with blind loops of bowel, or inflammatory bowel disease. After jejunoileostomy in patients with obesity, about 20% of the patients develop skin rashes.

After intestinal anastomosis, the bacteria abnormally proliferate in the blind loop. The intestinal bacteria, especially Escherichia coli, release the antigen peptidoglycan, stimulating the body to produce antibodies. Circulating immune complexes depositing in the skin cause blood vessel lesions, depositing in the synovial membrane of the joint cause tissue damage. At the junction of the epidermis and dermis, there are Escherichia coli antigens in the depositions, so it is speculated that Escherichia coli may play a role in the disease.

The initial skin lesions are small erythema, developing into red papules. Pustules, vesicles, or necrotizing vasculitis occur on the purple base within 48 hours, and finally central necrosis appears. Nodular erythematous and panniculitis-like lesions can also occur. Skin lesions are mainly in the upper limbs and torso, and may be related to the homomorphic reaction. Pustules are 0.5 - 15cm in diameter and often appear in groups. Each group of skin lesions lasts for 2 weeks, and repeatedly occurs after an interval of several months. Patients often have systemic symptoms such as fever, myalgia, diarrhea, abdominal cramps, joint pain or arthritis in the hands and wrists, tenosynovitis, and nephritis. Raynaud phenomenon may be present. Skin lesions can occur prior to systemic signs and symptoms.

Disseminated gonococcal infection

This disease is also known as gonococcal arthritis-dermatitis syndrome. If with bacteremia, there are fever and chills with polyarthritis and wandering arthritis. Elevated white blood cell count is common. Initial skin lesions are erythema, papules, or vesicles, with red halos, quickly progressing into pustules or bullae, which may be hemorrhagic or necrotic. Typical skin lesions are painful pustules on the basis of purpura, healing in few days, leaving small superficial scars.

Rheumatoid arthritis

In patients with rheumatoid factor-positive rheumatoid arthritis, localized pustular vasculitis, rheumatoid neutrophilic dermatosis, or even gangrenous pyoderma-like lesions can occur, mostly in patients with severe arthritis, and systemic symptoms such as fever are present.


Histopathology

Spongy pustules under the stratum corneum in or under the epidermis are visible. Histopathological changes of leukocytoclastic vasculitis, such as endothelial cell swellings, dense neutrophil infiltration, and karyorrhexis, can be seen in the dermis, but milder than leukocytoclastic vasculitis. The coexistence of pustules and vasculitis in histopathology is a prerequisite for the diagnosis of pustular vasculitis.


Diagnosis

On the basis of clinical presentations and histopathology, the disease can be diagnosed


Treatment

Colchicine inhibiting emigration of white cells, dapsone inhibiting leukocyte enzyme activity, potassium iodide, thalidomide, tetracycline, or erythromycin can be selected. For skin and joint symptoms, systemic glucocorticoids are generally unnecessary. Antibiotics should be used when infection. It has also been reported that treatment with cyclosporine is effective. For patients with intestinal anastomosis, surgical correction of the intestinal anatomy can relieve symptoms and signs.