Bacillary angiomatosis

What is bacillary angiomatosis?

Bacillary angiomatosis is an opportunistic cutaneous and systemic bacterial infection caused by Bartonella quintana and Bartonella henselae usually affecting immunocompromised patients.

Who gets bacillary angiomatosis?

Bacillary angiomatosis is seen predominantly with drug-induced immunosuppression, particularly organ transplant recipients, chronic lymphocytic leukaemia, and those with HIV/AIDS. However, otherwise healthy individuals, including children, can also contract the infection such as after major local trauma.

What is the cause of bacillary angiomatosis?

Bacillary angiomatosis is caused by Bartonella (Rochalimaea) quintana and Bartonella (Rochalimaea) henselae, gram-negative intracellular bacteria. Cats are the main reservoir for B henselae, and humans for B quintana. Although the infection may be spread via cat bites and scratches, fleas are the major route of transmission. B quintana is transmitted by the human body louse (Pediculus humanus) and fleas.

What are the clinical features of bacillary angiomatosis?

Skin lesions are usually the first manifestation of bacillary angiomatosis.

• Papules and nodules, range in size from pinpoint to 10cm
• Purple, violaceous, or bright red in colour
• Single lesion or many hundreds
• Any skin or mucosal site can be involved, although rarely the palms and soles
• In HIV, large subcutaneous tumours may form
• Lesions may bleed easily
• Overlying skin surface may become ulcerated or crusted

Figure 1

Figure 2

Figure 3

Figures 1&2: Helleberg M. Bacillary angiomatosis in a solid organ transplant recipient. IDCases. 2019;18:e00649.

Figure 3: Brzewski P, Kwiecińska M, Sułowicz J, et al. Bacillary angiomatosis in renal transplant recipient: a case report. Transplant Proc. 2020;52(8):2524-6

As the number of skin lesions increase, the patient may develop high fever, tender swollen lymph nodes, nausea, vomiting, sweats, chills, and poor appetite.

How do clinical features vary in differing types of skin?

Hyperpigmented indurated plaques have been described mainly in skin of colour.

What are the complications of bacillary angiomatosis?

The infection can cause blood vessels to grow out of control and form tumour-like masses in other organs including the brain, bone, gastrointestinal tract, and respiratory tract with airway obstruction. 

Liver involvement is called 'peliosis hepatis' or 'bacillary peliosis'.

How is bacillary angiomatosis diagnosed?

Bacillary angiomatosis should be suspected clinically, particularly in an immunocompromised patient.

Skin biopsy shows lobular blood vessel proliferation with epithelioid endothelial cells, and an inflammatory infiltrate including neutrophils. The microorganisms can be seen as basophilic clumps in the stroma and confirmed on Giemsa or Warthin-Starry stain. [see Bacillary angiomatosis pathology]

Polymerase chain reaction (PCR) can be used to identify the causative agent.

What is the differential diagnosis of bacillary angiomatosis? 

• Pyogenic granuloma
• Kaposi sarcoma
• Carrion disease

What is the treatment of bacillary angiomatosis?

• Erythromycin 500mg qid
• Doxycycline 100mg bd
• Other antibiotic options include trimethoprim + sulphamethoxazole, tetracycline, rifampicin

Antibiotics should be continued for 3-6 months to prevent recurrence.

Large pus-filled lymph nodes or blisters may need to be drained. Supportive therapy includes hydration and analgesics for pain and fever. Warm moist compresses to affected nodes may decrease swelling and tenderness.

What is the outcome of bacillary angiomatosis?

Cutaneous lesions of bacillary angiomatosis disappear with days to weeks of starting appropriate treatment, although response can be incomplete.

Spontaneous resolution has been reported.

Systemic bacillary angiomatosis can be fatal if not treated promptly.