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Erythrasma Skin Infection

Erythrasma is a very specific superficial and chronic infection of top layers of the skin caused by overgrowth of a Gram positive bacillus called Corynebacterium minutissimum which is usually present as a normal human skin inhabitant. Corynebacteria invade the upper one-third of the stratum corneum and under favorable conditions these organisms proliferate. This infection leads to pigmentation of pale fair-skinned individuals or depigmentation of dark-skinned people, but the incidence is higher in black people. It is characterized by reddish-brown slightly scaly patches with sharp borders appearing in moist areas of the body and lesions may itch slightly or be asymptomatic.

This superficial skin infection is observed all over the world with an incidence estimated around 4 percent. The widespread form is found more frequently in the subtropical and tropical areas than in other parts of the world. The incidence of erythrasma increases with age, but no age group is immune to the disease. Erythrasma mostly affects adults, especially those heavier individuals, and is observed most frequently during adolescence. The youngest patient reported to have this condition is a 1-year-old child.

Infection appears in areas where skin touches skin, being toe web spaces are the commonest site affected by this organism such as under the breasts and in the groin, axillae, armpits, webs of the toes, and genital areas, particularly in men, where the inner thighs touch the scrotum. In some people, the infection spreads to the torso and anal area, but in all cases erythrasma produce irregularly shaped pink patches that may later turn into fine brown scales that sometimes is confused with a fungal infection. Since it produces a porphyrin which fluoresces a striking coral pink color under radiation methods, it can be misdiagnosed as fungal infection.

Among the causes that lead to contract this infection we can enlist C minutissimum, a member of the normal skin flora, as the causative agent along with predisposing factors including obesity, diabetes mellitus, delicate cutaneous barrier, excessive sweating/hyperhidrosis and other immunocompromised states. Erythrasma is usually a benign condition that doctors can easily diagnose because skin infected with Corynebacterium glows coral red under exposure to long-wave ultraviolet radiation such as with a black light or UVA Wood's light where lesions are observed. Culture of scrapings from the lesion may be practiced for an accurate diagnose.

Wood's lamp is a test that is performed in a dark room where ultraviolet light is shined on the area of interest. No special preparation is needed, but if you are treating the area in question with any topical medications, you should skip an application before visiting the doctor. Light examination may be also negative if patient bathed prior to presentation but also gram stain reveals gram-positive rods. The diphtheroid bacteria are present in the horny layer as rods and filaments and it may become widespread and invasive in predisposed and immunocompromised individuals. The skin may present a wrinkled appearance with fine scales and well-demarcated, brown-red macular patches producing a macerated scaling appearance identical to a fungal infection.

Erythrasma does not usually cause any symptoms just presents as a slowly enlarging area of pink or and reddish-brown lesions in skin folds and moist areas of the body and mildly itchy. Infection may be treated with topical and oral agents. Antibacterial and anti-fungal agents are used to eradicate the condition and possible concomitant infection and an antibiotic given by mouth, such as erythromycin or tetracycline can eliminate the infection. Antibacterial soaps, such as chlorhexidine and topical imidazoles and/or fusidic acid may also help. Topical drugs including clindamycin and miconazole cream are effective as well. Clotrimazle, miconazle, econazle are also excellent aids. Five days treatment is usually enough but 2 to 3 weeks may be required due Erythrasma may recur in 6 to 12 months due moisture, being necessary for a second treatment.

This infection under-diagnosed or under-treated may present complications such as fatal septicemia in immunocompromised patients, post-surgical wound infection, and infective endocarditis in valvular heart disease. Prognosis is excellent, but the erythrasma tends to recur if the predisposing factors are not eliminated, so patients should be instructed to keep the area dry. Gently scrubbing on the lesions with antibacterial soap may clear the disease and calm the itching. The topical application of erythromycin gel is very effective as well. In severe cases, your doctor may prescribe oral erythromycin with complete recovery is expected following treatment.

As preventive measures to reduce the risk of acquiring erythrasma, keeping good hygiene is the most important. Keeping the skin dry and wearing clean absorbent clothing, such as cotton, avoidance of excessive heat and humidity. If you will be tested under Wood's lamp, there are no risks, but avoid looking directly into the ultraviolet light, as you avoid looking into the sun. And remember to contact your health care provider if you or any member of your family exhibits the scaly brown patches of erythrasma.