dermatology in general medicine

1. Cutaneous Tuberculosis

2. Introduction
infection by
Mycobacterium tuberculosis,
M. bovis and
occasionally by Bacillus Calmette-Guerin (BCG)
can be acquired either exogenously or endogenously
• The clinical manifestations depend on
• the site of infection,
• type of inoculum and the
• host's immunity

3. Etiological Agent
• Mycobacterium tuberculosis -
Weakly gram-positive,
strongly acid fast,
strictly aerobic,
non-motile,
non-spore forming,
curved rods
Cell wall has high content of mycolic acid-rich
Mycobacterium Bovis –
penetrate the gastro-intestinal mucosa and lymphatic tissue of the
oro-pharynx when ingested in milk.

4. Mycobacteria of dermatological interest

5. classification
EXOGENOUS
1. PRIMARY INOCULATION
TB- PREVIOUS NON
SENSITIZED HOST
2. Tuberculosis verrucosa
cutis- SENSITIZED HOST
3. LUPUS VULGARIS
OCCASIONALLY
ENDOGENOUS
BY CONTIGOUS SPREAD-
SCROFULODERMA
BY AUTO INCOCULATION- ORIFICAL TB
HEMATOGENOUS- LUPUS VULGARIS
TB GUMMA
MILIARY TB
TUBERCULID
LICHEN SCROFULOSORUM
PAPULONECROTIC
TUBERCULID
ERYTHEMA INDURATUM
OF BAZIN

6. PAUCIBACILLARY - TBVC, LUPUS VULGARIS
( GOOD IMMUNITY)
REST ALL MULTIBACILLARY
HENCE POOR IMMUNITY

7. EXOGENOUS
TB

8. Primary inoculation tuberculosis
(Tuberculous chancre, tuberculous primary complex)
–brownish papule,
–nodule, or
–ulcer with an undermined edge
Painless, non healing ulcer

9. Warty tuberculosis
(Tuberculosis verrucosa cutis, Anatomist’s warts, Prosector’s
warts, Verruca necrogenica)
• Sites of trauma
• indurated, warty papule

10. ENDOGENOUS TB

11. Scrofuloderma
(Tuberculosis colliquativa cutis)
• Direct extension from underlying tuberculosis FOCUS
• Commonest form worldwide
• Commonest form in children and adolescents in India
• An asymptomatic bluish red subcutaneous swelling
• Breaks down to form undermined ulcers or fistulas

12. Orificial tuberculosis
(Tuberculosis cutis orificialis)
• Advanced systemic TB, impaired immunity
• Sites
• pulmonary tuberculosis - lips and mouth
• intestinal tuberculosis - anal region
• genitourinary tuberculosis - external genitalia

13. Lupus vulgaris
Most common form of cutaneous TB in India
reddish brown, plaque
Grows by slow peripheral extension
• APPLE JELLY NODULES ON DIASCOPY

14. Acute cutaneous miliary tuberculosis
haematogenous dissemination
Crops of minute bluish papules, vesicles, pustules, erythematous nodules, or
haemorrhagic lesions

15. Metastatic tuberculous abscess
(Tuberculous gumma)
• subcutaneous nodule or a non-tender fluctuant abscess
• Commonly on extremities
• May break down to form an undermined ulcer, with sinuses

16. Tuberculids
• Cutaneous hypersensitivity reaction to hematogenous dissemination of
M. tuberculosis or its products in patient with significant immunity
(earlier concept)
• Following criteria must be fulfilled to designate a condition as
tuberculid:
– Tuberculoid histology on skin biopsy
– Strongly positive Mantoux reaction
– Absence of M. tuberculosis in smear
– Negative culture
– Resolution of skin lesions with antituberculous therapy

17. • True tuberculids can be grouped as
• Micropapular: lichen scrofulosorum.
• Papular: papulonecrotic tuberculid.
• Nodular: erythema induratum of Bazin or nodular tuberculid

18. LICHEN SCROFULOSURAM
• closely grouped lichenoid papules
• Usually Skin-coloured, but may be yellowish or reddish-brown

19. Papulonecrotic tuberculid
(Tuberculosis papulonecrotica)
• Recurring crops of asymptomatic, symmetrical, hard, dusky red papules

20. Erythema induratum of Bazin
(Nodular vasculitis, Bazin disease, Tuberculosis cutis indurativa)
• Tuberculosis‐associated panniculitis
• Usually calves, young or middle-aged women
• ill‐defined nodules or subcutaneous plaques

21. Atypical Mycobacteria
Causative agent Clinical features Investigations Treatment
M. Marinum
(Fish tank/
swimming pool
granuloma)
Nodule/pustule – break down into
ulcer/abscess. Sporotricoid pattern
Culture at 30-33° C
PCR DNA
Clarithromycin + Ethambutol ±
Rifampicin x3-4 months
(Resistant to isoniazid and
pyrazinamide)
M. Kansasii Papule/pustule/nodules/verrucous
plaques. Primarily pulmonary disease
Culture
PCR
Isoniazid + Rifampicin + Ethambutol
x18 months (Resistant to isoniazid)
M. Ulcerans
(Buruli ulcers)
Papule/nodule – ulcer -- Rapid spread
– Upto subcut, spare muscles
Smear. Culture at 32°
C. PCR
Rifampicin + Streptomycin
± Surgery (according to category)
M. Avium complex
(M. avium and M.
intracellulare)
Multiple ulcer, nodules, plaques,
abscess. Sporotrichoid spread. HIV
individuals more affected
Culture
(blood/marow)
AFB –ve. PCR
Clarithromycin + Ethambutol ±
Rifabutin ± Surgical excision
M. Haemophilum Erythematous/violaceus
papules/nodules – painful
abcess/ulcer. Panniculitis
Culture (30-32°C)
PCR
Clarithromycin + Ciproflox +
Rifamycin
M. Scrofulaceum Nodule/abscess/plaque/ulcer.
Swelling/sinus of submandibular and
submaxillary gland.
Culture
PCR
Surgery
Clarithro + Ethamb + Rifabutin
M. Szulgai Principally Pulmonary.
Cellulitis/nodules/sinus
Isoniazid, Rifampicin, Ethambutol,
Streptomycin

22. Laboratory Investigations
Absolute criteria-
• Demonstration of M. TB in either tissue culture or cytological smear
• Demonstration of mycobacterial DNA by PCR
Relative criteria-
• Presence of active, proven tuberculosis elsewhere
• Presence of acid‐fast bacilli in the lesion
• Positive reaction to tuberculin
• Positive IFN‐γ release assay
• Effect of specific therapy

23. MANTOUX TEST
DEMONSTRATION OF AFB- ZN STAIN
CULTURE
PCR
IGRA
HISTOPATHOLOGY
TRIAL OF ATT

24. TREATMENT
ATT

26. Drug Daily Dose Thrice-Weekly Dose
Isoniazid 5 mg/kg, max 300 mg 10 mg/kg, max 900 mg
Rifampicin 10 mg/kg, max 600 mg 10 mg/kg, max 600 mg
Pyrazinamide 25 mg/kg, max 2 g 35 mg/kg, max 3 g
Ethambutol 15 mg/kg 30 mg/kg
First line drugs
• Rifampicin(R)– Bactericidal, all bacilli
• Pyrazinamide(Z)– Bactericidal, all bacilli
• Isoniazid(H)– Bactericidal, replicating bacilli
• Ethambutol(E)– Bacteristatic

27. Newer drugs

28. WHO recommended drug regimens
• Culture and drug susceptibility testing (DST) for all previously treated TB
patients at or before the start of treatment
• In patients with HIV, treatment with isoniazid and rifampicin is continued for
seven months after the initial two months of quadruple therapy.

29. DOTS (directly observed treatment, short course)
• launched by WHO in 1995
• Category 3 regime under RNTCP abolished
• Only 2 regimes in effect (of 1st line drugs)
• Cat 1 for all new cases and Cat 2 for all retreatment cases
• Cat 1: 2 H3R3Z3E3 + 4 H3R3
• Cat 2: 2 H3R3Z3E3S3+ 1 H3R3Z3E3 + 5 H3R3E3
• Fixed drug combination (FDC) products such as
isoniazid/rifampicin, isoniazide/rifampin/pyrazinamide, and
isoniazid/rifampin/pyrazinamide/ethambutol are available as well

30. Multidrug-resistant (MDR) tuberculosis
• Defined as resistance to rifampicin and isoniazid with or without resistance
to other antituberculous drugs
• MDRTB found in lupus vulgaris, scrofuloderma, and tuberculosis cutis
• 3.6% of new and 20% previously tuberculosis (TB) patients in world have
MDR-TB
Extensively drug-resistant (XDR) TB
• XDR= HR + 1 FQ + 1 Injectable (KM or AMK or CM)
• 10% of MDR-TB cases are also extensively drug-resistant (XDR-TB)

31. Isoniazid and Rifampicin resistant-
• Pyrazinamide + ethambutol + quinolone (levoflox) + Streptomycin (or
another injectable) x 18-24 months
Resistant to all first line drugs-
• 1 injectable + 3 of the following
• Ethionamide, quinolone, cycloserine, PAS
x 24 months
Surgery
• Surgical excision of small lesions of lupus vulgaris or warty tuberculosis,
if diagnosed early
• Plastic surgery may help the disfigurement left by treated lupus vulgaris

32. Pregnancy-
• Ethambutol and streptomycin are contraindicated due to their teratogenic
effects
Renal Insufficiency-
• Interval or drug dosing should be adjusted in patients with creatinine
clearance <30ml/min
• Rifampicin - None
• Isoniazid - 50%
• Pyrazinamide 48 – 72h
• Ethambutol 25 – 50%
• Streptomycin 72 – 96h

33. Hepatic Insufficiency-
• Rifampicin, isoniazid and pyrazinamide have great hepatotoxicity potential
• Ethambutol can be fully utilized by patients with liver insufficiency
• To prevent isoniazid-related neuropathy, pyridoxine (10–25 mg/day)
should be added to persons at high risk of vitamin B6 deficiency such as
• Alcoholics, malnourished, pregnant and lactating women, chronic renal
failure, diabetes, HIV infection