Primary cutaneous nocardiosis.

A 35-year-old male presented with multiple discharging sinuses and fluctuant swelling on right side of face which started after a vehicular accident three year back. The lesions did not respond to routine antibiotics treatment but went on increasing. Gram smear showed typical acid fast branching filaments suggestive of nocardiosis, which was confirmed by culture. Patient received co-trimoxazole for three and a half month. When seen again after three years, all the lesions had healed with puckered scarring. Patient had received co-trimoxazole for three and a half months with dramatic improvement.

Introduction

Primary cutaneous nocardiosis is an uncommon disease. This infection, which is a cutaneous form, may mimic actinomycosis, hence causing a diagnostic dilemma. Here we report a primary cutaneous pattern in an immunocompetent host. A 35-year-old male presented with multiple discharging sinuses on face following a vehicular accident; diagnosis of which was confirmed by microbiological investigation and the patient responded to co-trimoxazole therapy for three and a half months.

Nocardia are aerobic, Gram positive, partially acid fast filamentous bacteria and are found as saprophytic organisms in soil. Primary cutaneous nocardiosis is an uncommon disease and human infection can occur either by inhalation of dust contaminated with Nocardia which causes pulmonary infection or contamination of wound with dust which causes cutaneous infection or by deep implantation due to thorn prick causing subcutaneous infection (mycetoma). Pulmonary infection is usually seen in immunocompromised, whereas cutaneous infection is usually seen in immunocompetent persons.[1] From lung the infection can get disseminated to involve other organs causing systemic infection including skin. N. asteroides are commonly implicated for pulmonary and systemic infections[2] and N. brasiliensis is commonly responsible for the skin and subcutaneous tissue infections.[2] This paper presents a clinical case of this uncommon disease emphasizing Nocardia as a causative agent in wound infection.

Case Report

In 2002, a 35-year-old male patient presented with multiple discharging sinuses on face for three years. Three years back, the patient had met with a vehicular accident which leads to lacerated wound on right side of face. Few weeks after the accident, the patient noticed pimple-like lesion at the site of wound. These lesions did not respond to local medications, rather went on increasing in number and size, and he went to a surgeon who excised the wound but the lesions recurred. Six months back, he was seen by a dermatologist and was diagnosed to have actinomycosis and was put on injection procaine penicillin for one month without any significant improvement. When the patient approached us, there were multiple tender fluctuant abscesses and discharging sinuses involving the frontal, temporal and small part of maxillary region with swelling of eyelids of right side [Figure 1]. However, there was no induration which is so characteristic of actinomycetoma. There were no grains.

Figure 1

Multiple dischargig sinuses present on right side of scalp, face, frontal region, temporal region and zygomatic region - lateral view

Looking at this picture, the differential diagnosis considered were actinomycosis, tuberculosis and osteomyelitis and the patient was further investigated. Blood count, blood sugar, urine analysis were within normal limits. ELISA for HIV was negative and X-ray of skull showed no bony involvement ruling out the possibility of osteomyelitis. Gram staining of the pus showed Gram positive branching filaments which on modified Zeil-Nelsons staining (decoloring with 1% H2SO4) showed partial acid fastness indicating Nocardia [Figure 2]. The diagnosis was confirmed when culture on L- J media grew dry granular pigmented colonies characteristic of Nocardia species. So the patient was put on tab septran (trimethoprim 160 mg + sulfamethoxazole 800mg) - 2 tablets BD. and Incision and drainage of some abscesses was also done. After one and a half month, the patient showed good improvement but lost to follow up. When he came again in 2007 for unrelated problem (T.Cruris), the face showed healed deep scars [Figure 3]. On enquiring, the patient reported to continue the same treatment for further two months and as all the lesions were healed, he did not turn up for follow up.

Figure 2

(a) Modified zeel - Neelson staning showing acid fast bascilli, (b) L-J Media showing dry granular pigmented colonies characteristic of Nocardia

Figure 3

Lateral view of face showing healed puckered deep scars

Discussion

Primary cutaneous nocardiosis occurs due to direct implantation of pathogenic Nocardia from soil to the skin. Primary cutaneous Nocardial infections are divided into (a) primary cutaneous nocardiosis (cellulitic and sporotrichoid forms), (b) disseminated disease (most common secondary to pulmonary involvement) and (c) actinomycetoma caused by Nocardia.[3] Deep inoculation in subcutaneous tissue leads to mycetoma formation, whereas superficial inoculation leads to pustules or abscess formation. Some times, from primary pustular lesion formed at the site of inoculation, the infection spreads through lymphatics causing lymphocutaneous form.

Nocardiosis has been reported worldwide. Around 500-1000 cases of nocardiosis are recognized in US each year.[4] However, in India, the number of reports of nocardial infection is limited.[4]

Mycetoma is the most common presentation of primary cutaneous nocardiosis. Mycetoma can be actinomycotic (caused by filamentous bacteria), eumycotic (caused by fungi) or botryomycosis (caused by true bacteria). In Mexico and central and south America, Nocardia accounts for 90% cases of actinomycotic mycetoma.[15] Nocardial infection is supposed to be uncommon in India, though it is reported from various parts of India like Himachal Pradesh in North,[6] Mumbai in western part[7] and Karnataka[8] in southern part of India. Talwar and Sehgal reported Nocardia in 35% of culture positive cases of mycetoma in north India.[9] Baxi and Mathur in their study of 73 cases of mycetoma from Rajasthan did not report a single case due to Nocardia.[10] In a study from Madras, Nocardia was found to cause mycetoma in 21% of cases.[11] Inamadar and Palit have reported 10 cases of primary cutaneous nocardiosis which includes 5 patients of mycetoma.[8] Sharma et al, has reported 4 cases of nocardial mycetoma from Himachal Pradesh.[6] Nocardial mycetoma on back causing epidural abscess and cord-compression has been reported.[12] Although the dissemination of Nocardia from mycetoma is rare, it has been reported.[1314]

Our patient presented with multiple discharging sinuses of chronic duration like typical mycetoma. There was no bony involvement nor was any dissemination of infection in our patient. Mycetoma being a chronic infection, it usually needs longer treatment than other forms of primary cutaneous nocardiosis. Despite the long duration of illness, severe involvement and requiring long-term treatment for mycetoma, it is unusual for our patient to show complete healing with just 3.5 months course of co-triamoxazole. Nocardial infection usually shows less of induration and more of suppuration;[415] hence probably relatively short duration of treatment is required as compared with other mycetoma. Fibrosis in other mycetoma offers resistance to antibiotic penetration in the lesion. In our patient, entire lesion was soft fluctuant without much of induration. Nocardial mycetoma differs from other mycetoma by being not fibrotic and may present without grain formation.[15] In other mycetomas, fibrotic reaction is very characteristic which gives rise to induration and tumefication. Nocardia infection should be suspected in any trauma-associated superficial cutaneous infections that do not respond to routine treatment.[1]

Nocardia are slowly growing organisms that may require one to two weeks before well sized colonies are formed and if the lab is not informed of the possibility of Nocardia it is reported as no growth after 48 h and the cultures are often discarded. Culture takes long time but Gram staining of the pus gives early indication of nocardiosis as in our case and hence very important before other investigations are requested. Species identification requires a specialized lab.

Co-trimoxazole is the mainstay of therapy. In systemic form of disease, other effective drugs such as dapsone, amikacin, amoxycillin, cephalosporins, minocycline, erythromycin, ciprofloxacin, imipenim and clindamycin can be used. One to four months of therapy is usually curative for superficial cutaneous nocardiosis whereas mycetoma may require prolong treatment. Minimal surgical intervention, in the form of draining an acute abscess, is sometimes needed. Complete healing of lesions with co-trimoxazole was observed in our patients at the end of three and a half months unlike mycetoma. Prognosis of all forms of primary cutaneous nocardiosis including nocardial mycetoma is good as it shows excellent response to co-trimoxazole as evident from our patient.

Cutaneous nocardiosis remains a diagnostic challenge.[16] A good microbiological lab facility is required for the diagnosis of nocardiosis.