A fast-growing cold skin abscess revealing disseminated Mycobacterium intracellulare infection in an HIV-infected patient.
Summary (1 min read)
Introduction
- A 66-year-old woman with HIV-1 infection recently commenced on antiretroviral therapy (CD4þ 25 cells/mm3 was referred to the Dermatology Clinic the following month due to a well-demarcated nodule in the extensor surface of the left arm with evident fluctuation but only slight pain on palpation, with no increase in temperature.
- Surgical drainage was performed with aspiration of yellowish-green exudate, with no characteristic smell.
- The patient was treated with clarithromycin, ethambutol and rifabutin for 24 months.
- M. intracellulare species and Mycobacterium avium constitute the Mycobacterium avium–intracellulare complex (MAC), responsible for the majority of human infections by atypical mycobacteria.
- Cutaneous infection is rare and may present clinically with erythematous plaques, chronic ulcers or abscesses.
Case report
- A 66-year-old female patient originally from GuineaBissau was referred to the Dermatology Clinic due to a fast-growing asymptomatic skin nodule on the left arm, present for one week.
- After appropriate medical treatment and the start of tenofovir/emtricitabine and raltegravir (TDF/FTCþRAL), the patient became asymptomatic and was discharged with residual lung disease on CT scan.
- This skin abscess was surgically drained, releasing an abundant odorless yellowish thick fluid that was fully aspirated and sent for culture – aerobic and anaerobic bacteria, fungi and mycobacteria.
- Direct examination of the skin exudate was negative, including for acid-fast bacilli.
- The skin nodule regressed after two weeks and computed tomography of the thorax showed no residual lung disease at nine months of therapy.
Discussion
- A global decrease in tuberculosis was accompanied by an increased awareness of atypical mycobacteria (AM) -associated disease.
- Due to similar clinical, etiological and antigenic similarities, some groups of AM are considered together as complexes: Mycobacterium avium and M. intracellulare are grouped together as the Mycobacterium avium–intracellulare complex (MAC).
- Regarding cutaneous AM disease occurring globally, several recent case series classify 65–86% of the affected patients as immunocompetent.
- 1,4,8 Primary cutaneous infection by MAC is rare, and excluding concomitant pulmonary disease is considered mandatory,9 especially in the context of immunosuppression.
- The variety of clinical manifestations is wide and non-specific, including erythematous plaques, ulcers and abscesses.
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Citations
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Cites background from "A fast-growing cold skin abscess re..."
...Dissemination from these locations typically occurs over several months.[2] We describe a case of deep skin and soft‐tissue MAC infection which secondary dissemination in a HIV‐negative patient....
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References
4,969 citations
"A fast-growing cold skin abscess re..." refers background in this paper
...pressed individuals, mainly in persons with advanced HIV infection, and the more frequent clinical presentation is lung disease or disseminated disease.(1) Figure 1....
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...The variety of clinical manifestations is wide and non-specific, including erythematous plaques, ulcers and abscesses.(1,3,6,7,10) As a crucial part of multidisciplinary teams, the dermatologist is on the front line of care for severely immunocompromised patients and a high level of suspicion is mandatory when approaching these cases....
[...]
...As most cases of cutaneous AM infection occur in immunocompetent patients and are limited to skin and soft tissues, other agents as Mycobacterium marinum or Mycobacterium fortuitum are much more commonly reported.(1,4,8) Primary cutaneous infection by MAC is rare, and excluding concomitant pulmonary disease is considered mandatory,(9) especially in the context of immunosuppression....
[...]
...Skin involvement revealing MAC disseminated disease has been rarely reported, both in healthy and in immunocompromised patients(6,7) and is not considered a typical clinical presentation.(1) According to most studies, the importance of MAC in cutaneous AM disease is limited....
[...]
...an increased awareness of atypical mycobacteria (AM) -associated disease.(1) Due to similar clinical, etiological...
[...]
231 citations
"A fast-growing cold skin abscess re..." refers background in this paper
...The variety of clinical manifestations is wide and non-specific, including erythematous plaques, ulcers and abscesses.(1,3,6,7,10) As a crucial part of multidisciplinary teams, the dermatologist is on the front line of care for severely immunocompromised patients and a high level of suspicion is mandatory when approaching these cases....
[...]
200 citations
96 citations
"A fast-growing cold skin abscess re..." refers background in this paper
...The variety of clinical manifestations is wide and non-specific, including erythematous plaques, ulcers and abscesses.(1,3,6,7,10) As a crucial part of multidisciplinary teams, the dermatologist is on the front line of care for severely immunocompromised patients and a high level of suspicion is mandatory when approaching these cases....
[...]
82 citations
"A fast-growing cold skin abscess re..." refers background in this paper
...avium; it tends to occur in patients who are severely immunocompromised, as evidenced by very low CD4þ T-cell counts.(5) Skin involvement revealing MAC disseminated disease has been rarely reported, both in healthy and in immunocompromised patients(6,7) and is not considered a typical clinical presentation....
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Frequently Asked Questions (11)
Q2. What is the predominant pathway to disease?
The MAC complex agents are ubiquitous slowgrowing pathogens and environmental exposure is considered the predominant pathway to disease.
Q3. What is the common cause of disseminated AM?
1Disseminated AM disease in HIV patients is due to MAC in >90% of cases, with more than 90% of those infections due to M. avium; it tends to occur in patients who are severely immunocompromised, as evidenced by very low CD4þ T-cell counts.
Q4. How many cases of MAC have been reported?
Regardingcutaneous AM disease occurring globally, several recent case series classify 65–86% of the affected patients as immunocompetent.
Q5. What is the role of the dermatologist in the care of patients with MAC?
As a crucial part of multidisciplinary teams, the dermatologist is on the front line of care for severely immunocompromised patients and a high level of suspicion is mandatory when approaching these cases.
Q6. What was the name of the patient?
The patient was kept on TDF/FTCþRAL in addition to clarithromycin 250mg bid, ethambutol 1200mg qd and rifabutin 300mg qd for 24 months.
Q7. How long did the MAC treatment last?
After 24 months of therapy, the immune status had improved (CD4þ cell count of 261 cells/mm3, viral load <20copies/mL) and the antimycobacterial therapy was stopped.
Q8. What was the name of the abscess?
This skin abscess was surgically drained, releasing an abundant odorless yellowish thick fluid that was fully aspirated and sent for culture – aerobic and anaerobic bacteria, fungi and mycobacteria.
Q9. What are the common agents in cutaneous AM?
As most cases of cutaneous AM infection occur in immunocompetent patients and are limited to skin and soft tissues, other agents as Mycobacterium marinum or Mycobacterium fortuitum are much more commonly reported.
Q10. What is the common type of MAC disease?
2–4 MAC disease, on the other hand, is much more common in immunosup-pressed individuals, mainly in persons with advanced HIV infection, and the more frequent clinical presentation is lung disease or disseminated disease.
Q11. What was the cause of the abscess?
One month after the first surgical drainage, Mycobacterium intracellulare was identified as the causative agent of the skin abscess (culture and nuclear hybridization).