Indian Journal of Dermatology, Venereology and Leprology Medknow Publications on behalf of The Indian Association of Dermatologists, Venereologists and Leprologists (IADVL) ISSN: 0378-6323 EISSN: 0973-3922 Vol. 71, Num. 2, 2005, pp. 128-129

Indian Journal of Dermatology, Venereology, Leprology, Vol. 71, No. 2, March-April, 2005, pp. 128-129

Letter To Editor

Ecthyma gangrenosum: A rare cutaneous manifestation caused by Pseudomonas aeruginosa without bacteremia in a leukemic patient

Singh Nabakumar, Devi Mamta, Devi Sulochana

Department of Microbiology, Regional Institute of Medical Sciences (RIMS), Imphal, Manipur
Correspondence Address: Department of Microbiology, Regional Institute of Medical Sciences (RIMS), Imphal - 795 004, Manipur
nabakr@rediffmail.com

Code Number: dv05040

Sir,

Ecthyma gangrenosum (EG) is a rare condition observed in neutropenic patients. It is caused by systemic infection most commonly with Pseudomonas aeruginosa, and has been related to life-threatening septicemia and high mortality.[1]

A 21-year-old woman was admitted with complaints of severe pain at the tip of the left little toe since five days and a necrotic lesion there since two days. This had been preceded by injury while she had been cutting the left little toenail, with slight oozing of blood followed by pain and bluish coloration of the left little toe. She had become febrile the next day, and had developed a warm, raised, tender indurated lesion on the tip of the left little toe the following day. The lesion had progressed over the next two days to a dark blister that had ruptured and developed central darkening. On examination, the ulcer was situated on the tip of the left little toe. It was 1 cm x 1.2 cm in size with an irregular shape, a ragged undermined margin, a raised hyperpigmented border and a slough-filled floor. It was tender and the base was indurated.

Results of her routine investigations were: peripheral WBC count, 85,000/cmm (neutrophils, 1%; lymphocytes, 6%; blast cells, 93%, of which 48% were of the hand mirror type; and eosinophils and monocytes, 0%); hemoglobin, 10 g/dL; platelet count, 35,000/cmm; ESR, 110 mm/hr; bleeding time, 1 min 36 sec; and clotting time, 4 min 30 sec. Bone marrow analysis revealed features of acute lymphoblastic leukemia (L2 subtype). Other tests were within normal limits. Blood cultures were repeatedly negative. Gram-stained smears from the necrotic lesion and from the surgical sample obtained by debridement showed no pus cells but occasional gram-negative bacilli. Cultivation of the pus swab revealed growth of Pseudomonas aeruginosa.

Treatment was initiated with amikacin, to which the isolates were susceptible, and the necrotic lesion was surgically debrided. The skin lesion resolved over a 21-day period. She was then treated with intravenous doxorubicin and vincristine for acute lymphoblastic leukemia; oral prednisolone and intrathecal methotrexate alternating with subcutaneous cytarabine were also administered.

Ecthyma gangrenosum is a characteristic dermatological manifestation of severe and invasive infection caused most commonly by Pseudomonas aeruginosa, and rarely by Klebsiella pneumoniae and other Pseudomonas species, e.g. Pseudomonas maltophilia, Pseudomonas burkholderia (cepacia). It occurs in 30% of patients with Pseudomonas aeruginosa septicemia,[2] but rarely it develops without bacteremia.

The pathogenesis of ecthyma gangrenosum caused by Pseudomonas aeruginosa in neutropenic patients is poorly defined. The primary inciting factor appears to be the presence of numerous viable organisms at the point of involvement. Dissolution of the elastic lamina of the blood vessels by Pseudomonas elastase allows for liberation of the bacilli into the subcutaneous tissues.[3] Further prolific multiplication of the organism in the subjacent tissue with elaboration of exotoxin A and proteases leads to the ulcerative lesion which is characterized by hemorrhage, encircled by a rim of reactive erythema.[4],[5]

The characteristic clinical appearance of ecthyma gangrenosum is a red macule that progresses to a central area of necrosis surrounded by an erythematous halo. This lesion represents a formidable skin sign of a potentially life-threatening systemic infection. The commonest site of involvement is the gluteal or perineal region. Metastatic lesions can appear on the trunk and lower limbs as seen in our patient. Almost all patients are neutropenic.

Treatment should include prompt recognition of the skin lesion, appropriate antibiotic therapy for Pseudomonas aeruginosa, and surgical debridement. Clinicians should be aware of the skin manifestations of ecthyma gangrenosum to avoid fatal septicemia in neutropenic patients.

REFERENCES

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