What are the signs and symptoms, laboratory investigations, and treatment,in case of  infection with Blastomyces dermatitis?

giorgiana1976 | Student

Blasto mycosis is a disease caused by infection of the human body with a fungus, Blastomyces dermatitis. Blastomycosis occurs by inhaling spores of Blastomyces (they are found mainly in wood and soil). The disease has a mortality reported to be between 0-2% (in patients immunocompetent) and about 40% in patients with AIDS.Age does not limit the risk to acquire such an infection, because there are cases reported in young children and elderly (ages extreme).

Signs and symptoms

Pulmonary infection can pass asymptomatic (at least in the initial stages), but if the process extends symptoms appear. Impaired of lung is asymptomatic in 50% of patients, and in other cases asymptomatic period is of 45 days (corresponding period of incubation). Not infrequently begins with multi organic diseases. The most commonly affected organs besides lungs, are the skin (in 20-40% of cases), also the bones (10-25%), prostate and other genitourinary organs (5-15%), meninges and brain (5 %). In rare cases, any organ can be affected equally, including the trachea or larynx, eyes and ears. Dissemination occurs especially in patients immunocompromised or with chronic lung disease.

The most common symptoms of blastomycosis  are:

- Chest pain

- Dyspnea, cough (often productive, with brown or reddish expectoration)

- Asthenia

- Fever

- Malaise, impaired health (Malaysia)

-  immobilized joints (with lithic bone involvement )

- Myalgia

- Skin rash (although most cases are missing)

- Sweating

- Sudden drop in weight

- Laryngitis

- Prostatitis (asymptomatic or can cause pain and burning when urinating).

The patient may describe symptoms that mimic a bacterial pneumonia (high fever, chills, productive cough and pleuritic pain) or tuberculosis in long-term damage (due to the evolution of chronic fever, night sweats, weight loss). Also, there are situations when the patient is presenting to hospital in serious condition with symptoms and events that seem to be adult respiratory syndrome: fever, dyspnea, tachypnea, diffuse pulmonary infiltration.

Laboratory investigations useful include:

Blood counts: white blood cell count determination can demonstrate the existence of a leukocytosis.

Pulse oximetry: patients with pneumonia present frequently hypoxaemia. Determination of blood gas is indicated in the presence of tachypnoea, hypoxaemia and pulmonary infiltrate presence.

Microscopic examination of sputum - a test is relatively simple to run, very useful in diagnosis of over 75% of patients with poor pneumonia. Is harvested a small amount of sputum,  on a knife and add a few drops of potassium hydroxide. Cover with a slide and examined microscopically.

Microscopic examination of other fluids, especially pus extracted from pustules or abscesses.

Most frequently performed imaging investigations are:

Radiograph of the chest

Computer tomography (CT) of thorax


Patients with blastomicosys quartered in the lung parenchyma did not require treatment unless the infection worse. Patients with subclinical disease should be observed. If the infection spreads rapidly and is increasingly worse, treatment should be instituted immediately. Hint of antifungal treatment also  have the patients with skin involvement (in this case there is not a spontaneous improvement and the patient may develop very ugly scars). Treatment should be instituted to keep in mind the type of damage, the enlargement process, the severity of symptoms, the immune status of patients and drug toxicity.

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