Introduction
Penicilliosis (also known as talaromycosis) is a rare fungal infection that occurs in immunocompromised people. Talaromyces marneffei (initially named Penicillium marneffei) was initially isolated from the liver of a bamboo rat. The first case of disseminated penicilliosis was reported in 1988 in a 61-year-old HIV (human immunodeficiency virus)-positive American missionary. Based on morphological traits, Talaromyces marneffei was previously classified as a member of the Penicillium subgenus Biverticillium. In 2011, it was discovered that the subgenus Biverticillium forms a monophyletic group with Talaromyces that is separate from Penicillium, and it was taxonomically unified with the Talaromyces genus. As a result, Penicillium marneffei was renamed Talaromyces marneffei, and penicilliosis was renamed talaromycosis.
What Is Penicilliosis?
Penicilliosis (talaromycosis) is a fungal infection that causes painless skin lesions on the face and neck, along with other symptoms like fever, anemia, swollen lymph glands, and liver damage. It is caused by the fungus Talaromyces marneffei, which is prevalent in soil and decomposing organic waste. The infection is considered to be acquired by inhaling the fungus from the environment, but the organism's environmental source is unknown. Penicilliosis usually occurs in people who are already sick and unable to fight infections, like old age, cancer patients, HIV or AIDS infection (acquired immunodeficiency syndrome), autoimmune diseases, and malnutrition. Generally, it does not affect healthy individuals.
What Causes Penicilliosis?
Penicilliosis (talaromycosis) is caused by Penicillium marneffei (Talaromyces marneffei), a fungus found in wild bamboo rats, their feces, and the soil around their tunnels. Human infection occurs primarily during the rainy season due to inhaling conidia from agricultural soil. The acute infection has a one to three-week incubation period; however, the latent infection might appear years later.
What Are the Risk Factors for Penicilliosis?
Penicilliosis (talaromycosis) affects those who are already unwell and unable to fight infection, such as those with HIV or AIDS, cancer, organ transplants, long-term steroid usage, old age, malnutrition, or autoimmune disease. Penicilliosis may also occur in association with certain conditions. It includes the following:
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Renal transplantation.
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Impaired cell-mediated immunity.
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Systemic lupus erythematosus.
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Hemolytic conditions (non-Hodgkin lymphoma).
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Following hematological transplantations.
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Treatment with monoclonal antibodies (Obinutuzumab and Rituximab).
What Are the Signs and Symptoms Associated With Penicilliosis?
Penicilliosis (talaromycosis) usually presents with small painless skin lesions in the head and neck. The liver, lungs, and mouth are usually affected in those without HIV infection, with systemic infection occurring rarely. The skin lesions are also often smooth. Penicilliosis presents differently in those with HIV infection; they are more likely to experience widespread infection. The skin lesions in HIV patients with penicilliosis are usually dented in the center and may look similar to molluscum contagiosum. Other symptoms associated with penicilliosis are the following:
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Fever.
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General discomfort.
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Cough.
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Weight loss.
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Diarrhea.
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Abdominal pain.
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Difficulty breathing.
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Splenomegaly (swelling of the spleen).
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Confusion.
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Altered mental state.
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Reduced consciousness.
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Lymphadenopathy (swollen lymph nodes).
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Hepatomegaly (liver swelling).
How Does Penicilliosis Appear on the Skin?
Skin lesions are prominent (70 percent) in HIV or AIDS-associated penicilliosis and are frequently the initial symptom. The lesions are characterized by papules with central necrosis or umbilication that are spread over the head and upper chest. In addition, there may be nodules, subcutaneous abscesses, pustules, cysts, and ulcers. The skin lesion in immune reconstitution inflammatory syndrome (IRIS)-associated penicilliosis is often atypical, with red papules, verrucous (warty) lesions, or plaques. In non-HIV-associated penicilliosis, the skin is involved in 40 percent of cases and may present with reactive rashes (sweet syndrome).
How Is Penicilliosis Diagnosed?
The diagnosis of penicilliosis is based on finding Penicillium marneffei (Talaromyces marneffei) in clinical specimen cultures such as sputum, blood, skin scrapings, lymph nodes, and bone marrow. Non-specific laboratory results, such as low platelets due to bone marrow infiltration and high transaminases due to liver involvement, may suggest signs of the fungus invading tissue. General screening blood tests often reveal leukocytosis with neutrophilia, anemia, thrombocytopenia, increased C-reactive protein (CRP), elevated liver enzymes, and ESR (erythrocyte sedimentation rate). Therefore, it is necessary to show the organism to diagnose penicilliosis. There are several ways to accomplish this. It includes the following:
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Blood, skin, or bone marrow culture.
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Rapid diagnostic methods based on PCR (polymerase chain reaction) or monoclonal antibodies.
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Microscopy of peripheral blood, touch smears from skin or lymph node biopsy, or histology.
What Is the Treatment for Penicilliosis?
Systemic antifungal medications are required to treat Penicilliosis. Initial high-dose therapy is given to the patients, followed by sustained maintenance over several months. The most commonly prescribed drugs are Amphotericin B, Itraconazole, and Voriconazole. Prophylactic treatment with the antifungal medicine Itraconazole is usually given to high-risk people.
Antifungal therapy for penicilliosis is divided into three phases, induction, consolidation, and maintenance. Induction therapy with Amphotericin B for two weeks, followed by consolidation therapy with Itraconazole for ten weeks, was demonstrated to be highly successful. Voriconazole has been used for induction therapy in patients who cannot tolerate Amphotericin B. Itraconazole is not suggested as induction therapy for penicilliosis, regardless of illness severity.
What Are the Complications of Penicilliosis?
Penicilliosis is frequently misdiagnosed, especially in HIV-negative patients from non-endemic regions. Once the infection has spread, the disease progresses swiftly. Disseminated penicilliosis can affect the bone marrow, resulting in anemia, thrombocytopenia, and the bones and joints, causing osteolytic lesions. In addition, penicilliosis is frequently accompanied by other opportunistic diseases in HIV-positive patients, such as tuberculous and non-tuberculous mycobacteria, which can conceal and delay diagnosis.
Conclusion
Penicilliosis is a rare infection caused by the dimorphic fungus Penicillium marneffei (Talaromyces marneffei). The condition is now named talaromycosis after reclassifying the caustic organism in 2011. This infection presents with painless skin lesions on the face and neck. It usually does not affect healthy people and does not transfer from person to person. Therefore, diagnosis is usually achieved by identifying the fungus from clinical specimens, either by microscopy or culture. Talaromycosis can be prevented in high-risk individuals by using the antifungal medicine Itraconazole, and it can be treated with Amphotericin B followed by Itraconazole or Voriconazole.
