Allescheriasis: causes, symptoms, diagnosis, and treatment

Allescheriasis is a mycetoma caused by Allescheria, particularly Allescheria boydii.


Causes

Pathogens cause infections after invading the human body. Patients often have a history of trauma, such as skin scratches, scrapes, or wounds. The most common pathogens are Allescheria boydii and Monosporium apiospermum, which can be isolated in soil and clothes.


Signs and Symptoms

Cutaneous allescheriasis

The disease is more common in middle-aged males, mostly on the exposed areas of the extremities, particularly the feet, as well as the calves, hands, and trunk. The initial lesions are papules and nodules, developing into multiple masses and abscesses, with dark red surface. Eventually, sinus tracts may form. The skin lesions can temporarily relieve and subside. The recurrences of the disease can involve the muscles, bones, fascia, and tendons over several months or years. There are numerous nodules, sinus tracts, local swelling, and scars. Serous purulent or oily fluids, mixed with yellow, white, or black particles, are often discharged from the sinus tracts, which is helpful for diagnosis and fungal identification. The systemic symptoms are mild, and there is little pain locally, and sometimes there is tenderness before the nodules rupture. Patients generally have no movement disorder. The course of disease can be as long as 10 - 20 years. However, if patients have dysimmunity and declined systemic resistance, dissemination may occur.

Systemic allescheriasis

Sysmtemic allescheriasis can be manifested by pulmonary allescheriasis, rhinosinusitis, maxillary sinusitis, meningitis, arthritis, endocarditis, keratitis, endophthalmitis, and otomycosis.

The destruction or hyperplasia of small bones can be seen in X-ray examination, and extensive infiltrating shadows are present in pulmonary allescheriasis.


Histopathology

Histopathological changes are mainly dense cicatricial tissues and inflammatory changes in local peripheral arteries caused by pyogenic granulomatous reactions. There are granules in the center of the abscesses, and the periphery is infiltrations of neutrophils, lymphocytes, giant cells, and plasma cells. Vascular proliferation can occur. The tendon and nerve tissue may be unchanged. Fibroblast proliferation can be seen in chronic lesions.


Diagnosis

On the basis of clinical manifestations, different colored particles in the pus, and fungi found in microscopy, the disease can be diagnosed.


Treatment

Early localized lesions can be treated with surgical excision, but lesions in deep tissues should be treated with systemic antifungals, such as itraconazole, and amphotericin B. Nystatin can also be effective to treat otomycosis.