Microsporidiosis is a mycotic disease of the skin, hair and nail plates. The causative agent is a keratinophilic mold fungus of the genus Microsporum, which parasitizes in keratinized substrates. There are about 50-70 cases of the disease per one hundred thousand people. Microsporidiosis is seasonal. Its incubation period is 4-6 weeks and ends with the appearance of a red and edematous spot on the skin. In the future, new elements appear that have a typical ring shape. Dermatoscopic and luminescent examination, detection of mycelium filaments in scraping from smooth skin helps to establish the diagnosis of microsporidiosis. Treatment is reduced to local and general use of antimycotic drugs.
Since the causative agent of microsporidiosis is widespread in nature, infection is possible everywhere, but in regions with hot and humid climates, microsporidiosis is diagnosed more often. The infection is transmitted by contact or through objects seeded with fungal spores. Children aged 5-10 years are more likely to suffer from microsporidiosis, while the incidence among boys is five times higher than among girls. Adults rarely suffer from microsporidiosis, but in the case of infection, the disease almost always self-cures due to the presence of organic acids in the hair, which inhibit the growth of mycelium.
The entrance gates for the causative agent of microsporidiosis are microtrauma of the skin; dryness, the presence of scuffs and callosities also increase the likelihood of infection, since healthy skin without damage is not available for inoculation of the fungus. The virulence of microsporidiosis is low, and therefore, with timely washing of hands, even those seeded with spores, the disease does not occur. Frequent contact with the ground, wild animals, sweating of the hands and violations of the chemical composition of the secretions of sweat and sebaceous glands increase the likelihood of microsporidiosis. In the soil, the spores of the causative agent of microsporidiosis persist from one to three months.
When introduced, the fungus begins to multiply and affects the hair follicle, after which the infection spreads to the entire hair, which leads to the destruction of the cuticle of the hair, between the scales of which the spores of the fungus accumulate. As a result, the mycelium of microsporidiosis completely surrounds the hair, tightly fills the bulb and forms a cover around the hair.
Microsporidiosis caused by an anthropophilic type of fungus has an incubation period of 4 to 6 weeks, after which a swollen red spot appears on the smooth skin, rising above the surface, it has clear outlines and gradually increases in size. Further, the lesions look like pronounced rings, which consist of nodules, bubbles and crusts. Rings are usually inscribed into one another or intersect, sometimes they tend to merge. The diameter of the rings in microsporidiosis ranges from 0.5 to 3 cm, and their number rarely reaches five.
In children and young women with microsporidiosis, a pronounced inflammatory reaction and a slight peeling of the lesions are possible. In patients who are prone to atopic dermatitis, microsporidiosis cannot be diagnosed in a timely manner, since the fungus often disguises itself as manifestations of dermatitis, and therapy with hormonal drugs only increases the symptoms and provokes the further spread of microsporidiosis.
Microsporidiosis of the scalp occurs in children aged 5 to 12 years, and by the time of puberty it passes without a trace. This phenomenon is associated with a change in the chemical composition of sebum and the appearance of organic acids in it and in the composition of the hair, which are harmful to the fungus. Microsporidiosis practically does not occur in children with red hair.
Lesions are located on the top of the head, on the parietal and temporal areas, usually microsporidiosis of the scalp manifests itself in the form of 1-2 large foci up to 5 cm in diameter with dropouts on the sides of smaller ones. At the site of the lesion, a flaky area occurs, since at first the fungus affects only the mouths of the hair follicles. Upon closer inspection, you can notice white ring-shaped scales that surround the hair like a cuff. After a week, the microsporidiosis spreads to the hair, they become brittle and brittle. The hair breaks off at a distance of 4-6 mm from the scalp, and the lesion area looks like a shorn one. The hair stumps are covered with mushroom spores and appear powdered with grayish-white powder. When affected by microsporidiosis, smoothed hair does not restore its original position, because it loses elasticity and elasticity. The scalp with microsporidiosis is swollen, slightly hyperemic, its surface is covered with grayish-white scales.
The suppurative form of microsporidiosis is clinically manifested by soft nodes of consistency, which are located on bluish-red skin. The surface of the nodes is covered with numerous pustules. When pressing on the infiltrate, droplets of pus are released through the holes. Suppurative forms of microsporidiosis occur with late medical treatment, irrational therapy and self-medication, as well as in the presence of serious concomitant diseases that reduce the protective properties of the body.
Clinical examination data and a history of contact with animals are sufficient for a dermatologist to suspect microsporidiosis. During dermatoscopy and microscopy of scraping, mycelium and changes in hair and skin characteristic of mycoses are detected. But the manifestations of microsporidiosis and trichophytia with conventional microscopy are identical, through this laboratory study it is only possible to confirm the presence of a fungal disease, but not to establish an accurate diagnosis.
Cultural diagnostics of microsporidiosis by sowing with subsequent detection of the pathogen is more informative, but requires more time, although it can be used to establish not only the type, but also the genus of the fungus, as well as to select the most effective drugs for treatment. Luminescent examination allows you to quickly examine both the patient with microsporidiosis and contact persons. The mycelium of the fungus glows with a green glow, but the cause of this phenomenon has not been studied. In the early stages of microsporidiosis, the glow may be absent, since the hair is not yet sufficiently affected. However, when removing the hair and subsequent examination in the root part, the glow is observed even at the end of the incubation period. The luminescent method makes it possible to identify the causative agent of microsporidiosis in the patient and those who have been in contact with him, as well as to evaluate the effectiveness of therapy.
Treatment and prevention
In the treatment of microsporidiosis, depending on the severity of the lesion, local and general antifungal therapy is used. Locally applied creams, ointments and emulsions with antifungal drugs – terbinafine and others, depending on the age of the patient and on the physiological state. It should be borne in mind that some antifungal drugs, even topical use during pregnancy and lactation, should be used with caution. Ointments and sprays of a new generation used for the treatment of microsporidiosis foci do not leave greasy spots on the skin and clothing, which will allow patients to feel comfortable during treatment.
If there is a pronounced inflammatory reaction, then use combined drugs that contain antifungal and hormonal components. Alternating applications with ointments and treatment with iodine solutions, if there is no skin lesion, has a good therapeutic effect. Microsporidiosis complicated by secondary infection is well treatable with an ointment that includes betamethasone, gentamicin and clotrimazole. For deep lesions, preparations containing dimethyl sulfoxide are used.
Prevention of microsporidiosis consists in regular examination of children in kindergartens to identify patients, in limiting contact with stray animals and in observing personal hygiene. The purchase of pets without a veterinarian’s examination can lead to intra-family outbreaks of microsporidiosis, which requires a more careful approach to their purchase.