Clinical and laboratory features of cutaneous tuberculosis

ARTICLE

Auteur(s) : Arzu Kiliç¹, Ülker Gül¹, Seçil Soylu¹, Müzeyyen Gönül¹, Murat Demiriz²

¹Ankara Numune Education and Research Hospital, 2nd Dermatology Clinic, Ankara, Turkey
²Gülhane Academy of Military Hospital, Pathology Department, Ankara, Turkey

accepté le 5 Mai 2009

Tuberculosis (TB) is still a serious health problem in both developing and developed countries. Cutaneous TB is relatively rare [1]. The aim of this report is to determine the clinicopathological and microbiological patterns of patients with cutaneous TB.

Eleven patients with cutaneous TB between 2005 and 2007 were included. The onset, localization and duration of the lesions, the time between the onset of symptoms to the diagnosis, the clinical and laboratory features, including purified protein derivative (PPD), direct microscopic examination of sputum and skin biopsy for Ziehl-Neelsen bacilli (ZNB), tuberculosis culture of sputum and skin biopsy, standard polymerase change reaction (PCR) of sputum and skin biopsy, fungal and bacterial cultures of skin biopsies, chest X-ray, thorax computerized tomography, Venereal Disease Research Laboratory (VDRL) and HIV tests were performed and the treatment protocols were recorded. All the patients were followed up until the discontinuation of treatment.

Eight patients were female, three were male. Their ages ranged from 15 to 72 years (mean age: 49.8 years). The period between the onset of lesions and the time of the diagnosis ranged from 1 to 47 years (mean: 14.5 years). No patient had TB in the past medical and family history. The characteristics of the patients are seen in table 1. None of our patients had anti HIV positivity. One had anti HCV positivity. Antituberculous treatment consisting of two months of quadruple therapy (isoniazid, rifampicin, pyrazinamide, and ethambutol) and followed by a further eight months with isoniazid plus rifampicin were started and all patients responded to therapy (figures 1A and B).
Table 1 The clinical and laboratory features of patients with cutaneous TB

Tuberculosis still continues to be a serious health problem in developing countries and it is also on the increase in developed countries. Cutaneous TB is relatively rare with an incidence of 0.1-4.4% of all cases [1, 2]. The correct diagnosis of cutaneous TB is usually missed or delayed due to the wide variety of clinical presentations and lack of consideration of the disease in differential diagnosis, due to false-negative cultures and negative direct-smear detection [2, 3]. Tissue culture is still the gold standard for the diagnosis of TB. However, due to the low number of bacilli in cutaneous TB, especially in LV, culture is often negative [4]. Detection of Mycobacterium tuberculosis by PCR is a reliable method for diagnosis and confirmation of cutaneous TB [5]. However, PCR has several limitations and its sensitivity is reduced in smear negative forms or in paucibacillary forms [2, 3]. Because of the non-homogeneous distribution of small numbers of bacilli, multiple sampling should be performed. Because of the high cost, PCR technique is not practical in developing countries [6]. Therefore, the diagnosis is mainly based on the Mantoux test, the histopathological appearance, and the response to antituberculous therapy [2, 5]. A strongly positive PPD reaction of >15 mm in diameter should be considered of diagnostic value [4]. In addition, improvement in the lesions with anti-tuberculous therapy suggests the diagnosis. In cutaneous TB, a period of 4-6 weeks of anti-tuberculous treatment is sufficient to confirm a diagnosis, in unresponsive cases an alternative diagnosis should be sought [3, 6].

We suggest cutaneous TB should be considered especially in long standing cases, and cases should be investigated for internal organ involvement. In areas of high TB prevalence, antituberculous therapy should be considered in suspected cases which are clinically and histopathologically consistent with cutaneous TB. In strongly suspected cases, antituberculous therapy is not only used as a treatment, but also as an essential component of the diagnosis.

Acknowledgements

References

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