Treating Secondary Infection In A Patient With Severe Tinea Pedis

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Michael Moharan, DPM, Mohamed Abdelmegeed Ahmed, MD, DPM, and Oleg Karpenko, MD, DPM

   Ecthyma gangrenosum is a rare but pathognomonic form of pseudomonal infection. Although ecthyma gangrenosum is often due to Pseudomonas, case reports indicate that the same frequency is associated with non-Pseudomonas ecthyma gangrenosum (i.e., Fusarium, Klebsiella). Ecthyma gangrenosum in patients without neutropenia is very rare as are non-bacteremic ecthyma gangrenosum cases. However, non-septicemic cases occur in patients without immunosuppression or neutropenia, or following antibiotic therapy. Pseudomonal burn wound infections occur with systemic involvement (e.g., bacteremia, fever, hypothermia, disorientation, obtundation, hypotension, oliguria, ileus and leukopenia). Chronic paronychia slowly evolves and initially presents with tenderness and mild swelling about the proximal and lateral nail folds. Pseudomonal toe web infections are distinctive clinical entities that are often misdiagnosed as tinea pedis.

   Dried exudate or a green stain (caused by pyoverdin) may be present on socks or toenails. Pseudomonas folliculitis presents as cutaneous lesions any time from eight hours to five days or more (mean incubation period is 48 hours) after using a contaminated whirlpool, home hot tub, water slide, physiotherapy pool or contaminated loofah sponge. Malaise and fatigue may occur during initial days of the eruption. Fever (uncommon) is low grade when present. Localized cellulitis can occur as a secondary infection of tinea of the toe webs or groin. It may also be triggered by bedsores, stasis ulcers or burns. Localized cellulitis can also occur in grafted areas or under the foreskin of the penis.
Maceration or occlusion of these skin lesions leads to secondary infection. Deep erosions and tissue necrosis may occur before one correctly diagnoses the condition.

   Severe pain is highly characteristic of an evolving infection. The hallmark lesions resulting from pseudomonal wound infections are multifocal with dark-brown to black or violaceous discoloration of the burn eschar. This is accompanied by edema and hemorrhagic necrosis.

   Ecthyma gangrenosum lesions are multiple noncontiguous ulcers or solitary ulcers. These lesions begin as isolated, red, purpuric macules that become vesicular, indurated and eventually, bullous or pustular. The bullae may be hemorrhagic but contain little if any pus. Lesions can remain localized or more often can extend over several centimeters. The central area of these lesions becomes hemorrhagic and necrotic. Then the lesion denudes to form a gangrenous ulcer with a gray-black eschar and erythematous halo. Although lesions can occur anywhere, they occur mainly in the gluteal and perineal regions (57 percent), the extremities (30 percent), the trunk (6 percent) and the face (6 percent).5

   These skin lesions heal slowly. Patients with septicemia have associated signs that include elevated temperatures, chills, hypotension, tachycardia and tachypnea. In chronic paronychia, the skin around the nail becomes pale, red, painful and swollen. A small amount of pus may occasionally emanate from beneath the proximal nail fold. The nail plate turns green-black, which is characteristic of pseudomonal infections. The condition causes little discomfort or inflammation.

   This presentation is often confused with subungual hematoma. A Pseudomonas-infected toe web presents as a thick, white, macerated scale with a green discoloration.

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man ying leesays: September 23, 2012 at 5:41 am

I have seen patients with Pseudomonas aeruginosa infection secondary to interdigital fungi infection. Instead of using topical cream, I use silver dressing with exudate control ability such as Aquacel Ag or Acticoat with aligiste m, together with oral antibiotics. The infected toe webs dried up, became less swollen and the foot healed up within two weeks.

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