What is Chromomycosis?
Chromomycosis (chromomycosis: Greek. Chrōma color, color + mycosis / s /, Pedroso’s disease, verrucous dermatitis) is a chronic fungal infection of the skin and subcutaneous tissue caused by dark-colored fungi of the Dematiateae family, representatives of which are widely distributed in the environment (earth, decaying wood, straw, etc.).
Causes of Chromomycosis
There are three main types of pathogens of chromomycosis: Fonsecae pedrosoi, Phyalophora verrucosa, Fonsecae compacta. All three types of micromycetes give macroscopically similar colonies. These fungi differ by microscopy according to the methods of sporulation: type Cladosporium, type Phialophora, and type Rhinocladiella,
Type 1 Cladosporium / Hormodendron. Sporulation occurs on conidionocells derived from the vegetative mycelium. At the distal end, two or more conidia are formed, of which in turn secondary conidia appear, then tertiary, etc. Long chains of conidia are formed. Hyphae of mycelium, conidionaceae and conidia are dark olive to brown. This type of sporulation is characteristic of Fonsecae pedrosoi, the causative agent of chromomycosis in Europe and Russia.
Type 2 Phyalophora. In this type of sporulation, fialids are formed along the mycelium or terminal. Phialides are peculiar conidionos in the form of “vases”, having a rounded, oval or elongated base and a narrowed neck. There is a curved “collar” around the hole on the top of the fialida. Conidia form fialida at the bottom and are ejected through the neck, concentrating in clusters around the fialida. This type of sporulation is characteristic of Phialophora verrucosa, the causative agent of chromomycosis in the countries of South America and the USA.
Type 3 Rhinocladiella / Acroteca. Conidionosos are simple, indistinguishable from vegetative mycelium. Oval conidia are produced directly at the ends and along the conidionus. Conidia are simple, do not budge and do not form chains. Mycelium, conidionaceae and conidia are greenish-brown. This type of sporulation is characteristic of Fonsecae compacta, a rare causative agent of chromomycosis in various parts of the world. It should be emphasized that for Fonsecae pedrosoi (the most frequent pathogen in Russia), all three types of sporulation are possible, with a clear predominance of the Cladosporium type.
Pathogenesis during Chromomycosis
Infection occurs as a result of traumatic implantation of the pathogen into the skin. For the occurrence of no need for an immunosuppressive state of the human body. Defeat is limited, as a rule, by skin and hypodermic cellulose. More often lower limbs are affected. But hands, skin of chest and abdomen, face skin may be affected. Without treatment, the course of chromomycosis is chronic with gradual progression. Described rare cases of brain damage and internal organs.
The primary lesion appears on the skin at the site of pathogen introduction in the form of a flaky tubercle or a congestive-red node. Over time, often months or years later, new nodes appear next to each other. Gradually, the lesion increases in size and takes on the appearance of growing plaques with verrucuse-papillomatous growths on the surface. Between plaques canes of healthy skin can be located. The surface of the plaques is covered with scales-crusts formed during the drying of purulent-hemorrhagic exudate. Often, tumor-like growths take the form of cauliflower, are easily injured, bleed, suppurate, and ulcerate. In place of the resolved foci, coarse hypertrophic scars resembling keloids are formed. The infection spreads through the lymphatic vessels and through autoinoculation. The lesions have eccentric growth, reach 10-20 cm in diameter, can cover the entire leg or foot. In advanced cases, lymphedema of the affected limb, elephantiasis, develops.
Symptoms of Chromomycosis
The classification of Carrion chromomycosis, expressed in 1950 and then undergone, in general, minor changes. There are five main clinical variants of chromomycosis:
- Nodular. Erythematoid papules sometimes with scaly surface. This is the initial type of lesion.
- Tumor. Large nodules with papillomatous or lobular surface, often covered with brown crusts. Possible severe vegetation.
- Verrukozny. Rash resemble vulgar warts at first.
- Scale hyperkeratotic. Flat foci of infiltration of various sizes and shapes, sometimes with papillomatous growths.
- Scar. It is characterized by atrophic sclerotic areas in the center of the lesions and the presence of fresh rashes on the periphery. The shape of lesions annular or arcuate.
This classification, of course, is only a scheme that allows for the simultaneous existence of lesions of various types and their consecutive transformation.
The incubation period is several weeks or months. At the beginning, an erythematous squamous lesion, resembling plaque psoriasis, appears at the site of the pathogen introduction. Subsequently, depending on what it is transformed into, papillomatous-ulcerative, bumpty or nodular forms of chromomycosis are isolated. The papillomatous-ulcerative form is characterized by a center of oval or oblong shape with a diameter of 10 cm and more, with sharp scalloped borders, a smooth infiltrated edge; the lesion is covered with crusts, when removed, ulcerations with warty growths and a small amount of bloody purulent discharge are detected. Sometimes papillomatous growths reach a height of 1 cm; they may resemble cauliflower.
When the tubercle form forms a tubercle of cyanotic-red conical shape, prone to peripheral growth. In the future, its color becomes dark brown; the tubercle is covered with a crust, new elements appear around it, merging into a conglomerate in the form of dense plaques with a scalloped edge. Then the tubercles soften, ulcerate, become covered by papillomatous growths.
When nodular (gummous) form in the hypodermis nodes are the size of 3-4 cm or more, dense consistency; they are located on a dense infiltrate. The skin above them is cyanotic. The nodes soften with the formation of crusted ulcers, when they are removed, papillomatous vegetation is exposed. For many years, slowly progressing, usually benign, there may be cases of dissemination process in the internal organs.
Diagnosis of Chromomycosis
The diagnosis of chromomycosis is made on the basis of a characteristic clinical picture, microscopic and / or cultural studies of pathological material (scales, crusts, pus). In diagnostically difficult cases, pathological examination is necessary.
The diagnosis of chromomycosis is confirmed by the presence of tissue forms of the fungus in the so-called substrates (scales, histological sections) in the form of so-called sclerotic cells, fumago or dark bodies, which are rounded dark pigmented cells with a double-contoured wall, dividing into two or three parts by a transverse partition . Tissue forms never bud. When culturing flakes, biopsy specimens on Saburo medium, a slowly growing colony appears (2-3 weeks) from olive green to black.
The treatment of chromomycosis is carried out by a dermatologist-mycologist in the hospital; prescribe amphotericin B, potassium or sodium iodide; topical – 20% pyrogallic plaster, Gordeev’s liquid, antifungal ointments.
The prognosis is favorable; with the dissemination process in the internal organs, the brain may be fatal.
Prevention of chromomycosis is not fully developed; it is important to protect the skin from injury, their timely treatment with disinfectants (for example, an alcohol solution of iodine).