Bacillary angiomatosis

Bacillary angiomatosis is a systemic illness characterised by lesions similar to those of Kaposi sarcoma in the skin, mucosal surfaces, liver, spleen and other organs. It is caused by bacterial infection with Bartonella quintana and Bartonella henselae (cause of catscratch disease and also known as Rochalimaea henselae). The disease is only rarely seen in healthy immunocompetent people. It mostly affects patients with immunodeficiency, particularly those with AIDS or HIV.

How do you get bacillary angiomatosis?

Bacillary angiomatosis is caused equally by Bartonella quintana and Bartonella henselae. It is usually a result of exposure to flea-infested cats with Bartonella henselae and the human body louse for Bartonella quintana (cause of trench fever in soldiers during World War I). Nowadays, the disease occurs mainly in AIDS patients. It may also be a complication of catscratch disease in immunocompetent patients.

What are the clinical features of bacillary angiomatosis?

The first sign is usually the appearance of numerous pinpoint purplish to bright red raised spots and nodules up to 10cm on or just under the skin. These lesions resemble Kaposi sarcoma and often the disease is mistaken for this. There can be anywhere between 1 to 100 lesions occurring on any part of the body, although they are rarely found on the palms, soles, or in the mouth. Lesions may be pinhead sized spots or nodules up to 10cm in diameter. Nodules are firm lumps and do not turn white with firm pressure. If injured, the lesions bleed profusely.

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

The infection can also causes blood vessels to grow out of control and form tumour-like masses in other organs including the bone, liver, spleen, lymph nodes, heart, gastrointestinal tract and respiratory tract where airway obstruction may occur. The condition can become life threatening if not diagnosed and treated promptly.

How is bacillary angiomatosis diagnosed?

Bacillary angiomatosis should be suspected clinically particularly in HIV/AIDS patients. Skin biopsy is required to distinguish it from Kaposi sarcoma. Histology of bacillary angiomatosis can be difficult to distinguish from pyogenic granuloma but the microorganisms can be demonstrated on Warthin-Starry stain.

What is the treatment of bacillary angiomatosis?

Bacillary angiomatosis is effectively treated with antibiotics. Erythromycin appears to be the antibiotic of choice and is given until lesions resolve, usually within 3-4 weeks of starting therapy. Other antibiotics used include doxycycline, trimethoprim + sulphamethoxazole, tetracycline and rifampicin.

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.