The etiology and pathogenesis of microbial (paratraumatic, near-wound ) eczema , in contrast to the etiology and pathogenesis of true eczema, are well studied. It has been established that the antigenic properties of the pyococcal flora of pathogenic fungi, including yeasts, are capable of sensitizing the skin. Elevated titers of strepto- and staphylokinase , streptolysin -0 and staphylolysin , positive skin -allergic reactions with specific antigens, detection of serum autoantibodies to tissue antigens confirm the presence of an allergic condition and sensitization to streptococcus and staphylococcus in patients with microbial eczema [Zverkova F. A., 1975; Skripkin Yu. K. et al., 1983]. The development of sensitization to the microbial antigen is favored by neuroendocrine disorders, changes in metabolic processes, and immunity.
These reasons cause the development of a peculiar clinical picture of microbial eczema, which differs significantly from other types of eczema. Microbial eczema usually begins as an asymmetric process on the skin of the legs, back of the hands, and scalp. The lesion has borders (often with a “fringe” of the exfoliating stratum corneum of the epidermis), is characterized by a mild tendency to dissemination of rashes. The borders of the foci (acute inflammatory erythema, exudative papules, microvesicles , pustules) are often curved, on their surface there are accumulations of greenish-yellow, serous -purulent and bloody crusts, erosions.
The surface of the areas free from crusts, red or stagnant – red, bleeds
easily. Sometimes there is a point weeping characteristic of eczema ( serous or
eczematous wells). Periodic exacerbations of the disease lead to increased
itching.
The development of microbial eczema often begins with the appearance of
pustules, acute inflammatory erythema and exudative papules along the periphery
of the trophic ulcer of the leg, in the area of the postoperative stump, around
the fistulous tract due to improper application of a plaster cast, irrational
treatment of the skin around the wound with an alcoholic solution of iodine,
etc.
In these cases, microbial eczema is called paratraumatic, or near-wound . There
are several varieties of microbial eczema: nummular , varicose, sycosiform ,
nipple eczema).
Nummular eczema
It is characterized by the appearance of slightly raised above the level of the skin, sharply limited lesions of rounded outlines (diameter 1-2 cm or more), the presence of swelling, erythema, exudative papules and pronounced drip weeping , a tendency to dissemination of the process. The disease is prone to recurrence and is highly resistant to therapy.
In children, microbial eczema is usually combined with foci of chronic infection (otitis media, rhinitis, sinusitis, frontal sinusitis, chronic tonsillitis, conjunctivitis) and other streptostaphylococcal lesions [Zverkova F. A., 1975].
Microbial eczema is also characterized by the appearance during the
period of exacerbation of the process of secondary allergic rashes –
polymorphic microbids . More often these are erythematous scaly spots or
papular, papulovesicular rashes, accompanied by intense itching. In some cases
(with an increase in sensitization), they can transform into true eczema with
the formation of a large number of fast -opening microvesicles and point
erosions with drip weeping .
Varicose eczema
Its occurrence is facilitated by a varicose symptom complex in the lower extremities. The lesions are localized in the area of dilated veins, along the circumference of varicose ulcers, areas of skin sclerosis . The development of the disease is favored by injuries, hypersensitivity of the skin to drugs used to treat varicose ulcers, and maceration of the skin when bandages are applied.
Polymorphism of elements, sharp, clear boundaries of foci, moderate
itching are characteristic, which makes varicose eczema clinically similar to
microbial and paratraumatic.
Sycosiform eczema
It can be observed in persons suffering from sycosis complicated by eczematization . On an inflamed edematous background, follicular pustules appear, penetrated in the center by a hair, often recurrent.
Sycosiform eczema is characterized by the pathological process going
beyond the limits of hairiness, the presence of eczematous wells, weeping ,
severe itching, and further development of lichenification . The favorite
localization of the process is the upper lip, beard, axillary folds, pubis.
Eczema of the nipples and pigment circle in women
It is characterized by the presence of foci of crimson color, covered with crusty scales, accompanied by weeping , the appearance of cracks. The process is very persistent. Often, eczema of the breast nipples is the result of trauma when breastfeeding a child or the result of complicated scabies.