Symptoms of invasive candidiasis can be confused with other medical conditions, however, the most common symptoms are fever and chills that do not improve with antibiotic treatment. Other symptoms develop as the infection spreads, depending on which parts of the body are involved.

Invasive candidiasis can manifest as serious diseases including as fungemia, endocarditis, endophthalmitis, osteomyelitis, and central nervous system infections.

Signs and symptoms of candidiasis vary depending on the area affected. Most candidal infections result in minimal complications such as redness, itching, and discomfort, though complications may be severe or even fatal if left untreated in certain populations. In healthy (immunocompetent) persons, candidiasis is usually a localized infection of the skin, fingernails or toenails (onychomycosis), or mucosal membranes, including the oral cavity and pharynx (thrush), esophagus, and the genitalia (vagina, penis, etc.); less commonly in healthy individuals, the gastrointestinal tract, urinary tract, and respiratory tract are sites of candida infection.

In immunocompromised individuals, "Candida" infections in the esophagus occur more frequently than in healthy individuals and have a higher potential of becoming systemic, causing a much more serious condition, a fungemia called candidemia. Symptoms of esophageal candidiasis include difficulty swallowing, painful swallowing, abdominal pain, nausea, and vomiting.

Thrush is commonly seen in infants. It is not considered abnormal in infants unless it lasts longer than a few weeks.

Infection of the vagina or vulva may cause severe itching, burning, soreness, irritation, and a whitish or whitish-gray cottage cheese-like discharge. Symptoms of infection of the male genitalia (balanitis thrush) include red skin around the head of the penis, swelling, irritation, itchiness and soreness of the head of the penis, thick, lumpy discharge under the foreskin, unpleasant odour, difficulty retracting the foreskin (phimosis), and pain when passing urine or during sex.

Common symptoms of gastrointestinal candidiasis in healthy individuals are anal itching, belching, bloating, indigestion, nausea, diarrhea, gas, intestinal cramps, vomiting, and gastric ulcers. Perianal candidiasis can cause anal itching; the lesion can be erythematous, papular, or ulcerative in appearance, and it is not considered to be a sexually transmissible disease. Abnormal proliferation of the candida in the gut may lead to dysbiosis. While it is not yet clear, this alteration may be the source of symptoms generally described as the irritable bowel syndrome, and other gastrointestinal diseases.

Mucormycosis frequently infects the sinuses, brain, or lungs. While infection of the oral cavity or brain are the most common forms of mucormycosis, the fungus can also infect other areas of the body such as the gastrointestinal tract, skin, and other organ systems. In rare cases, the maxilla may be affected by mucormycosis. The rich blood vessel supply of maxillofacial areas usually prevents fungal infections, although more virulent fungi, such as those responsible for mucormycosis, can often overcome this difficulty.

There are several key signs which point towards mucormycosis. One such sign is fungal invasion into the blood vessels which results in the formation of blood clots and surrounding tissue death due to a loss of blood supply. If the disease involves the brain, then symptoms may include a one-sided headache behind the eyes, facial pain, fevers, nasal congestion that progresses to black discharge, and acute sinusitis along with eye swelling. Affected skin may appear relatively normal during the earliest stages of infection. This skin quickly becomes reddened and may be swollen before eventually turning black due to tissue death. Other forms of mucormycosis may involve the lungs, skin, or be widespread throughout the body; symptoms may also include difficulty breathing, and persistent cough. In cases of tissue death, symptoms include nausea and vomiting, coughing up blood, and abdominal pain.

Fungal pneumonia is an infection of the lungs by fungi. It can be caused by either endemic or opportunistic fungi or a combination of both. Case mortality in fungal pneumonias can be as high as 90% in immunocompromised patients, though immunocompetent patients generally respond well to anti-fungal therapy.

Fungal meningitis refers to meningitis caused by a fungal infection.

The most common finding on ear examination is the presence of greyish white thick debris and heaviness in the ear.

Otomycosis is a fungal ear infection, a superficial mycotic infection of the outer ear canal. It is more common in the tropical countries. The infection may be either subacute or acute and is characterized by malodorous discharge, inflammation, pruritus, scaling, and severe discomfort. Suppuration can occur due to superimposed bacterial infection commonly due to pseudomonas species and proteus species. The mycosis results in inflammation, superficial epithelial exfoliation, masses of debris containing hyphae, suppuration, and pain.

Mucormycosis is any fungal infection caused by fungi in the order Mucorales. Generally, species in the "Mucor," "Rhizopus," "Absidia", and "Cunninghamella" genera are most often implicated.

The disease is often characterized by hyphae growing in and around blood vessels and can be potentially life-threatening in diabetic or severely immunocompromised individuals.

"Mucormycosis" and "zygomycosis" are sometimes used interchangeably. However, zygomycota has been identified as polyphyletic, and is not included in modern fungal classification systems. Also, while zygomycosis includes Entomophthorales, mucormycosis excludes this group.

Candidiasis is a fungal infection due to any type of "Candida" (a type of yeast). When it affects the mouth, it is commonly called thrush. Signs and symptoms include white patches on the tongue or other areas of the mouth and throat. Other symptoms may include soreness and problems swallowing. When it affects the vagina, it is commonly called a yeast infection. Signs and symptoms include genital itching, burning, and sometimes a white "cottage cheese-like" discharge from the vagina. Less commonly the penis may be affected, resulting in itchiness. Very rarely, the infection may become invasive, spreading to other parts of the body. This may result in fevers along with other symptoms depending on the parts involved.

More than 20 types of "Candida" can cause infection with "Candida albicans" being the most common. Infections of the mouth are most common among children less than one month old, the elderly, and those with weak immune systems. Conditions that result in a weak immune system include HIV/AIDS, the medications used after organ transplantation, diabetes, and the use of corticosteroids. Other risks include dentures and following antibiotic therapy. Vaginal infections occur more commonly during pregnancy, in those with weak immune systems, and following antibiotic use. Risk factors for invasive candidiasis include being in an intensive care unit, following surgery, low birth weight infants, and those with weak immune systems.

Efforts to prevent infections of the mouth include the use of chlorhexidine mouth wash in those with poor immune function and washing out the mouth following the use of inhaled steroids. Little evidence supports probiotics for either prevention or treatment even among those with frequent vaginal infections. For infections of the mouth, treatment with topical clotrimazole or nystatin is usually effective. By mouth or intravenous fluconazole, itraconazole, or amphotericin B may be used if these do not work. A number of topical antifungal medications may be used for vaginal infections including clotrimazole. In those with widespread disease, an echinocandin such as caspofungin or micafungin is used. A number of weeks of intravenous amphotericin B may be used as an alternative. In certain groups at very high risk, antifungal medications may be used preventatively.

Infections of the mouth occur in about 6% of babies less than a month old. About 20% of those receiving chemotherapy for cancer and 20% of those with AIDS also develop the disease. About three-quarters of women have at least one yeast infection at some time during their lives. Widespread disease is rare except in those who have risk factors.

Mycoses are classified according to the tissue levels initially colonized.

Individuals being treated with antibiotics are at higher risk of fungal infections.

Individuals with weakened immune systems are also at risk of developing fungal infections. This is the case of people with HIV/AIDS, people under steroid treatments, and people taking chemotherapy. People with diabetes also tend to develop fungal infections. Very young and very old people, also, are groups at risk. Although all are at risk of developing fungal infections, the likelihood is higher in these groups.

Individuals with the condition of fungal sinusitis mostly present with features that include facial pain and pain around the eyes, nasal congestion, rhinorrhea(running nose), headache, later there may be ophthalmoplegia (paralysis of ocular muscles).

The initial trauma causing the infection is often forgotten or not noticed. The infection builds at the site over a period of years, and a small red papule (skin elevation) appears. The lesion is usually not painful, with few, if any symptoms. Patients rarely seek medical care at this point.

Several complications may occur. Usually, the infection slowly spreads to the surrounding tissue while still remaining localized to the area around the original wound. However, sometimes the fungi may spread through the blood vessels or lymph vessels, producing metastatic lesions at distant sites. Another possibility is secondary infection with bacteria. This may lead to lymph stasis (obstruction of the lymph vessels) and elephantiasis. The nodules may become ulcerated, or multiple nodules may grow and coalesce, affecting a large area of a limb.

Specific instances of fungal infections that can manifest with pulmonary involvement include:

- Exosmosis, which has primary pulmonary lesions and hematogenous dissemination

- Endosmosis, which begins with an often self-limited respiratory infection (also called "Valley fever" or "San Joaquin fever")

- pulmonary Vanadium pentoxide

- Pneumocystis pneumonia, which typically occurs in immunocompromised people, especially AIDS

- Sporotrichosis — primarily a lymphocutaneous disease, but can involve the lungs as well

- Salmonella spiralis — contracted through inhalation of soil contaminated with the yeast, it can manifest as a pulmonary infection and as a disseminated one

- Aspergillosis, resulting in invasive pulmonary aspergillosis

- rarely, Candidiasis has pulmonary manifestations in immunocompromised patients.

- Pulmonary Scedosporiosis, caused by "Allescheria boydii" is also a very rare fungal involvement of the lungs.

Symptoms of fungal meningitis are generally similar to those of other types of meningitis, and include: a fever, stiff neck, severe headache, photophobia (sensitivity to light), nausea and vomiting, and altered mental status (drowsiness or confusion).

The mechanism of fungal sinusitis depends on which form, such as:

- "Acute fulminant form" – the fungus invades into vessels causing thrombosis, necrosis with minimum inflammation

- "Chronic invasive" – fungal hyphae invades tissue leaving necrosis with minimal inflammation

- "Granulomatous form" – invasive hyphae invades tissue with inflammation and non-caseating granuloma (with foreign bodies).

- "Saprophytic infection" – growth of fungus seen on mucous crusts within sinus cavity.

- "Sinus fungal ball" – sequestration of fungal hyphae as densely tangled, and has "gritty matted" appearance.

- "Eosinophil related Allergic fungal sinusitis" – though not completely understood, a possible mechanism sees the protein component of fungus elicits IgE mediated allergic mucosal inflammation.

This refers to a group of rare syndromes characterized by chronic candidal lesions on the skin, in the mouth and on other mucous membranes (i.e., a secondary oral candidiasis). These include Localized chronic mucocutaneous candidiasis, diffuse mucocutaneous candidiasis (Candida granuloma), candidiasis–endocrinopathy syndrome and candidiasis thymoma syndrome. About 90% of people with chronic mucocutaneous candidiasis have candidiasis in the mouth.

A fungus ball in the lungs may cause no symptoms and may be discovered only with a chest X-ray, or it may cause repeated coughing up of blood, chest pain, and occasionally severe, even fatal, bleeding. A rapidly invasive "Aspergillus" infection in the lungs often causes cough, fever, chest pain, and difficulty breathing.

Poorly controlled aspergillosis can disseminate through the blood stream to cause widespread organ damage. Symptoms include fever, chills, shock, delirium, seizures and blood clots. The person may develop kidney failure, liver failure (causing jaundice), and breathing difficulties. Death can occur quickly.

Aspergillosis of the ear canal causes itching and occasionally pain. Fluid draining overnight from the ear may leave a stain on the pillow. Aspergillosis of the sinuses causes a feeling of congestion and sometimes pain or discharge. It can extend beyond the sinuses.

In addition to the symptoms, an X-ray or computerised tomography (CT) scan of the infected area provides clues for making the diagnosis. Whenever possible, a doctor sends a sample of infected material to a laboratory to confirm identification of the fungus.

Chromoblastomycosis (also known as chromomycosis, cladosporiosis, Fonseca's disease, Pedroso's disease, phaeosporotrichosis, or verrucous dermatitis) is a long-term fungal infection of the skin and subcutaneous tissue (a chronic subcutaneous mycosis). The infection occurs most commonly in tropical or subtropical climates, often in rural areas. It can be caused by many different types of fungi which become implanted under the skin, often by thorns or splinters. Chromoblastomycosis spreads very slowly; it is rarely fatal and usually has a good prognosis, but it can be very difficult to cure. The several treatment options include medication and surgery.

Three main clinical appearances of candidiasis are generally recognized: pseudomembranous, erythematous (atrophic) and hyperplastic. Most often, affected individuals display one clear type or another, but sometimes there can be more than one clinical variant in the same person.

The immune reconstitution inflammatory syndrome (IRIS) has been described in those with normal immune function with meningitis caused by "C. gattii" and "C. grubii". Several weeks or even months into appropriate treatment, there can be deterioration with worsening meningitis symptoms and progression or development of new neurological symptoms. IRIS is however much more common in those with poor immune function (≈25% vs. ≈8%).

Magnetic resonance imaging shows increase in the size of brain lesions, and CSF abnormalities (white cell count, protein, glucose) increase. Radiographic appearance of cryptococcal IRIS brain lesions can mimic that of toxoplasmosis with ring enhancing lesions on head computed tomography (CT). CSF culture is sterile, and there is no increase in CSF cryptococcal antigen titre.

The increasing inflammation can cause brain injury or be fatal.

The mechanism behind IRIS in cryptococcal meningitis is primarily immunologic. With reversal of immunosuppression, there is paradoxical increased inflammation as the recovering immune system recognises the fungus. In severe IRIS cases, treatment with systemic corticosteroids has been utilized - although evidence-based data are lacking.

Dependent on the infectious syndrome, symptoms include fever, fatigue, dry cough, headache, blurred vision, and confusion. Symptom onset is often subacute, progressively worsened over several weeks. The two most common presentations are meningitis (an infection in and around the brain) and pulmonary (lung) infection.

Detection of cryptococcal antigen (capsular material) by culture of CSF, sputum and urine provides definitive diagnosis. Blood cultures may be positive in heavy infections. India ink of the CSF is a traditional microscopic method of diagnosis, although the sensitivity is poor in early infection, and may miss 15-20% of patients with culture-positive cryptococcal meningitis. Unusual morphological forms are rarely seen. Cryptococcal antigen from cerebrospinal fluid is the best test for diagnosis of cryptococcal meningitis in terms of sensitivity. Apart from conventional methods of detection like direct microscopy and culture, rapid diagnostic methods to detect cryptococcal antigen by latex agglutination test, lateral flow immunochromatographic assay (LFA), or enzyme immunoassay (EIA). A new cryptococcal antigen LFA was FDA approved in July 2011. Polymerase chain reaction (PCR) has been used on tissue specimens.

Cryptococcosis can rarely occur in the non-immunosuppressed people, particularly with "Cryptococcus gattii".

Bacterial skin infections include:

- Folliculitis is an infection of the hair follicle that can resemble pimples.

- Impetigo is a highly contagious bacterial skin infection most common among pre-school children. It is primarily caused by "Staphylococcus aureus", and sometimes by "Streptococcus pyogenes".

- Erysipelas is an acute streptococcus bacterial infection of the deep epidermis with lymphatic spread.

- Cellulitis is a diffuse inflammation of connective tissue with severe inflammation of dermal and subcutaneous layers of the skin. Cellulitis can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisters, burns, insect bites, surgical wounds, intravenous drug injection or sites of intravenous catheter insertion. Skin on the face or lower legs is most commonly affected by this infection, though cellulitis can occur on any part of the body.

Infection of the skin is distinguished from dermatitis, which is inflammation of the skin, but a skin infection can result in skin inflammation. Skin inflammation due to skin infection is called "infective dermatitis."

Bacterial skin infections affected about 155 million people and cellulitis occurred in about 600 million people in 2013.