What is Candidiasis?

Candidiasis is a fungal disease caused by Candida, especially Candida albicans. The pathogen can invade the skin and mucous membranes as well as affect the internal organs. Usually classified by the affected area, the two most common syndromes are mucosal cutaneous candidiasis (such as oropharyngeal candidiasis or thrush, esophagitis and vaginitis) and invasive or deep organ candidiasis (such as candidiasis Disease, chronic disseminated or hepatosplenic candidiasis, endocarditis, etc.). In most patients, candidiasis is an opportunistic infectious disease.

Basic Information

English name

candidiasis; candidosis

Visiting department

Infectious Diseases

Common locations

Skin, mucous membranes, internal organs

Common causes

Candida

Causes of candidiasis

The pathogen of this disease is Candida, which not only widely exists in nature, but also can be parasitic on normal human skin, oral cavity, gastrointestinal tract, anus and vaginal mucosa without causing disease. It is a typical condition pathogen. Candida albicans is the main pathogen of this disease. It is oval in shape under normal circumstances and symbiotic with the body and does not cause disease. In addition, there are a few other pathogenic bacteria in the genus Candida, such as Candida crocus, Candida sphaeroides, and Candida tropicalis. The pathogenicity of Candida is relative. The source of a Candida infection can be exogenous, ie candidiasis can be infected by contact with external bacteria. Candida infections can also be obtained from the hospital environment; however, most infections are endogenous infections, that is, Candida in the oropharynx, digestive tract, vagina, etc. The normal flora is changed to a pathogenic phase due to changes in the internal and external environment and decreased human immune function, which causes infection.

Clinical manifestations of candidiasis

Candida infections have no gender differences and can affect any age group, including unborn fetuses. Infection can invade almost all tissues and organs of the human body. Disseminate candidiasis involving multiple systems or organs, including bloodstream infections of Candida.

Mucosal skin candidiasis

(1) Oropharyngeal candidiasis: Candida albicans oropharyngitis is the most common, also known as acute pseudomembranous candidiasis and thrush. Candida albicans stomatitis is common in the tongue, soft palate, buccal mucosa, gums, and pharynx. The patient was conscious of pain, difficulty swallowing, and loss of appetite. Children and the elderly are the most common; newborns appear a week after birth; adult candida albicans stomatitis is rare. For patients with long-term use of broad-spectrum antibacterial drugs, corticosteroids, immunosuppressive agents, radiotherapy, chemotherapy, and leukemia and malignant tumors, if they have candida stomatitis, they should be highly vigilant whether they have been accompanied by respiratory, digestive, or even Candida sporadic infection. Further fungal inspections should be made in a timely manner.

(2) Esophageal candidiasis Candida esophagitis is mainly found in patients with malignant tumors and AIDS. It is manifested as esophageal spasm, dysphagia, burning sensation behind the sternum, and occasionally can cause major upper gastrointestinal bleeding. Esophagoscopy showed stained plaques and extensive inflammation on the mucosa.

(3) Vaginal candidiasis is the second vaginal infection second only to bacterial vaginitis, manifested as vaginal wall congestion and edema, and the vaginal mucosa is covered with a gray-white pseudomembrane. It is sticky and thin, and typical cases are accompanied by small white dregs. The vulva involves visible erythema, erosion, ulcers, and cleft palate, which can extend to the perianal region or even the entire perineum. Vulvar swelling, burning sensation, and severe itching are prominent symptoms of this disease, which can cause eczema-like changes due to scratching irritation over time. Vaginal candidiasis is more common in pregnant women and is also common in diabetic patients. Others can also be seen due to wearing tight pants and the use of broad-spectrum antibacterial drugs. It can be transmitted to men through sexual intercourse, causing candida balanitis or foreskin balanitis. Those who are too foreskin are susceptible to infection.

2. Candidiasis of the skin

(1) Candidiasis rubbing often involves the parts of the smooth skin that rub directly against each other. Such as armpits, under breasts, groin, perianal area, gluteal groove, perineum, etc. Sweaty, moist, and poorly ventilated. It is more common in obese middle-aged women and children. It starts with erythema, pimples, or small blisters in the rubbing area, and then the erythema, which is clearer, expands. After the blister is broken, it will desquamate or form an erosive surface, with a small amount of exudation, occasionally chapped and pain. It is satellite-shaped and often consciously itch.

(2) Chronic cutaneous mucosal candidiasis is rare. Mainly seen in patients with congenital T lymphocyte dysfunction. It usually develops within 3 years of age. Oral candidiasis occurs first, especially Candida albicans stomatitis, which then affects the whole body skin. It manifests as erythematous scaly rash, thinning hair loss, premature appearance and proliferative skin lesions. Sometimes oyster shell or cortex.

3. Disseminated candidiasis

For severe life-threatening fungal infections. Due to multiple organ involvement, clinical manifestations are diverse.

(1) Candida is positive for single or multiple blood cultures of Candida, but there is no evidence of organ involvement. It is more common in patients with agranulocytosis or other high-risk patients. The most common clinical manifestation is fever, which can often exceed 38 ° C. Occasionally chills and lowered blood pressure.

(2) Acute disseminated candidiasis manifests as persistent fever, and broad-spectrum antibacterial treatment is ineffective. The affected areas can be meningitis, brain abscess, encephalitis, myocarditis, endocarditis, osteomyelitis, arthritis, myositis (muscle tenderness) and so on. Endophthalmitis occurs in 30% of non-granulocyte-deficient individuals with blurred vision and eye pain. Ophthalmological examination shows retinitis, choroiditis, vitreous abscess, and even anterior chamber abscess, etc., unilateral or bilateral, can cause blindness. Involved in the skin, there are painful red papules with clear edges, with necrotic eschar, deep abscesses, gangrenous deep pustular lesions, cellulitis, nodules, etc. Those with thrombocytopenia may have purpura.

(3) Chronic disseminated candidiasis is also known as hepatosplenic candidiasis. When leukemia patients are relieved after treatment, white blood cell count returns to normal, and weight continues to decrease, the disease should be highly suspected. Often other organs are involved at the same time. Patients with hepatosplenomegaly, conscious abdominal pain, blood alkaline phosphatase can be significantly increased, and other liver function tests are normal or mildly abnormal.

4. Deep organ candidiasis

(1) Urinary tract candidiasis Most of disseminated candidiasis of the kidney affects the kidney, and a few are caused by ascending urinary tract infection. The main symptoms are fever, chills, low back pain and abdominal pain. Often results in the formation of a kidney abscess or hydronephrosis or anuria due to bacterial clogging. Babies often oliguria or no urine. Candida bladder inflammation is similar to bacterial cystitis, with frequent urination, pain, urgency, dysuria, and hematuria. Urine test was positive.

(2) Lower respiratory tract candidiasis is mostly endogenous infection of bronchial and pulmonary candida.

(3) Candida osteomyelitis and arthritis are manifested as local pain, which can form fistulas and osteolysis, but often without fever, and are more common in the lumbar spine and ribs. Candida arthritis can be seen after joint treatment, such as aspiration of joint fluid, intra-articular injection or artificial joint implantation. Mostly the blood line dissemination of disseminated candidiasis.

(4) Peritoneal and Candida bile infections Candida peritonitis is generally seen in patients with hemodialysis, gastrointestinal surgery, and abdominal organ perforation. Antibiotics have been previously used as risk factors. Infections are usually limited to the abdominal cavity. Patients with chronic peritoneal dialysis have very little dissemination. Infant spread is relatively common. Candida infections can also affect the gallbladder and bile ducts.

(5) Candida endocarditis is more common in patients with heart valve disease, intravenous drugs, undergoing cardiac surgery or cardiac catheterization. Sudden or insidious onset, fever, loss of appetite, fatigue and weight loss, anemia, etc.

(6) Candida meningitis For low-weight neonates who have been infected with Candida, debilitated or neurosurgical patients, but more commonly seen in patients with disseminated candidiasis.

(7) Candida endophthalmitis is spread by bloodstream or directly inoculated during surgery, manifesting as blurred vision, floating blind spots, and eye pain.

Candidiasis test

Laboratory tests include direct microscopy and culture methods, pathological methods, serological methods, and molecular biological methods.

Direct microscopy

Different specimens were taken according to the site affected by the infection, and potassium hydroxide wet push slides were prepared, or smears were examined under a microscope with Gram staining. Positive people can see the presence of a large number of spherical budding yeast and pseudohyphae, which have diagnostic value.

2. Fungal culture

Candida culture can be performed on patients with negative smears. The culture inspection method can further increase the positive rate of pathogen detection, verify the results of direct microscopy, and determine the type of pathogenic bacteria.

3. Histopathology

Patients suspected of having Candida esophagitis should not only undergo endoscopic brush specimen examination, but also biopsy to further find evidence of Candida invasion of mucosa from histopathology.
The tissue response of deep Candida is not characteristic. It is usually acute purulent or necrotic, and may have multiple abscesses or microabscesses, containing a large number of neutrophils, pseudohyphae and spores. Pseudohyphae and spores in the tissue are confirmed evidence of deep candidiasis.

4.G test and GH test

Patient specimens were collected for 1,3--D glucan test (G test) and galactomannan test (GH test). It can be used for the diagnosis of deep fungal infections and mycemia in patients with hematological malignancies, except for zygote and cryptococcus. The test specimens were blood, bronchopulmonary lung lavage fluid and cerebrospinal fluid. Sensitivity and specificity of serological tests are above 80%. However, false positive and false negative results of serological diagnosis are common, so the results of serological tests cannot be used as the basis for confirmatory diagnosis.

5. Immunological test

Candida albicans antibodies can be detected by double immunodiffusion method or latex coagulation method. The detection of serum candida polysaccharide antigen by ELISA or AB-ELISA method is more timely and accurate for the diagnosis of some systemic and disseminated candidiasis.

Candidiasis diagnosis

The diagnosis of cutaneous mucosal candidiasis depends on many types of specific clinical manifestations, and judgments are made in conjunction with fungal examination. In addition to the clinical manifestations of visceral candidiasis, multiple and multiple cultures of the same species are needed to confirm the diagnosis. Given that Candida is one of the normal flora of the human body, sputum, feces, and vaginal secretions are simply culture-positive, which only indicates the presence of Candida and cannot be diagnosed as Candida. Direct microscopic examination should see false mycelia and spores. The presence of silk indicates a pathogenic state. In short, it is necessary to diagnose whether the patient has a deep fungal infection according to whether the patient has high-risk factors of the host, clinical manifestations, and mycological evidence.

Candidiasis treatment

Commonly used drugs are nystatin, fluconazole, itraconazole and the like.

Body surface infection

Such as oral, vulva, vaginal candida albicans infection treatment: local treatment is the main treatment of light, serious systemic treatment. Oral infections are usually treated with a 2% to 4% carbonic acid (baking soda) solution, mouthwash, gentian violet rubbing, or chlorhexidine. The antifungal external medicines are given on the basis of rinsing and gargle, such as coating with nystatin emulsion, miconazole powder, tincture, and miconazole cream. The course of treatment is generally 7 to 10 days.

2. Mycotic vulvovaginitis

Basic medicine is usually used to flush the vagina. If 2% to 4% of soda solution is used to change the living environment of mold, and then choose antifungal external medicine, it can be placed with nystatin vaginal suppository, local nystatin cold cream, 1% Apply 5% clotrimazole ointment or cream. When the infection is severe or the effect of local treatment is poor, oral antifungal drugs are added. Optional oral antifungal.

3.Various visceral candidiasis and severe cutaneous mucosal candidiasis

(1) Nystatin This drug is rarely absorbed in the intestine and is mainly used for digestive tract candidiasis.

(2) The course of ketoconazole depends on the type of infection and the response of the patient. Use with caution in patients with abnormal liver function.

(3) Itraconazole

(4) Intravenous infusion of amphotericin B , or combined with oral 5-fluorouracil can have a certain synergy to improve the efficacy.