Download MBBS Dermatology PPT 4 Cutaneous Tuberculosis Lecture Notes

Download MBBS (Bachelor of Medicine, Bachelor of Surgery) Dermatology PPT 4 Cutaneous Tuberculosis Lecture Notes



ETIOLOGY- Mycobacterium Tuberculosis

PATHOGENESIS- manifestations of lesions depend


1.Immunity of the host
Specific immunity to M. Tuberculosis ? depending

on whether exposure to the bacteria is primary or


General immunity of the host

2. Route of entry

3. Bacterial load


1.Exogeneous source

Tuberculous chancre

Warty tuberculosis/ TVC

Lupus vulgaris

2.Endogenous source

a. contiguous source ? Scrofuloderma

b. auto-inoculation ? Oroficial T.B.

c. hematogenous - Lupus vulgaris,

Tuberculous gumma

3.Tuberculides ?

a. Micropapular ? Lichen scrofulosorum

b. Papular, Papulo-necrotic

c. Nodular? Erythema nodosum

Erythema induratum(Bazin)

Tuberculous Chancre
No prior immunity to M. tuberculosis

( Primary complex in the skin)
Entry?cuts, abrasion, insect bites, wounds
Site- exposed areas of limbs, face
Age - children

Clinical feature

Nodule ulcerates

producing tuberculous


Crusts form and edges

become indurated


lymphadenopathy in

few weeks

Dev. Of immunity

lesion heal to produce

a scar

Warty Tuberculosis/ Tuberculosis Verrucosa


Exogenous source
Moderate to high immunity to M.


Occupational- who handle tuberculous

tissue eg. butcher, pathologist,

veterinarians (anatomist wart)

Site ? hands, feet

Single indolent

verrucous nodule or

plaque with a

serpenginous border,

indurated base, centre

may show scarring.

Heals in several

months leaving thin

atrophic scar

Lymphadenopathy rare

Scrofuloderma/ Tuberculosis Cutis


Develops as an extension of an underlying

focus ? lymph node or bone

Site ? cervical region common with

infected cervical lymph nodes breaking

down into the skin

Infected lymph nodes

become inflamed,

swollen, get fixed to

overlying bluish skin

Breakdown of lymph

nodes formation of

ulcers with undermined


AFB can be


Orificial Tuberculosis/ Tuberculosis Cutis


Develops from auto inoculation around the

muco cutaneous junctions in patients with

internal tuberculosis

Site- lips, mouth in pulmonary T.B.

anal region in intestinal T.B

external genitalia in genitourinary T.B

Host immunity poor with active internal


Small erythematous

nodules break

down, form round,

shallow, granulating

ulcers covered by

thin crust.

No tendency to heal

without effective


Tuberculin test may

be -ve

Lupus Vulgaris
most common form of cut. TB
Usually acquired from an external source;

rarely from haematogenous dissemination

Site ? around nose (nasal mucosa and

lips) and face in western countries

buttocks, thighs, legs in India

Initial lesion is a soft erythematous nodule

Slowly several such nodules coaslesce to

form a soft plaque which slowly extends

Presence of APPLE JELLY nodules at edge

of plaques- in diascopy( uncommon in

Indian skin)

MATCH STICK sign ? soft nodules can be

probed or pierced with a match skick

Diseases relentlessly progresses with

irregular extension of the plaque

Healing occurs with SCARRING

Occasional ulceration, crusting and

scarring with destruction of underlying

tissues and cartilage- ULCERATIVE and


Tuberculous Gumma
Results hematogenous dissemination from

a tubercular focus

Usual in malnourished children

The lesion is initially a subcutaneous

nodule which breaks into the skin to form

an ulcer with an undermined edges.

Symmetrical eruptions

Result of internal focus of tuberculosis,

though internal disease may not be active.

Patient health is good.

Prob. Cause hematogenous dissemination of

bacilli in a person with high degree of


Tuberculin test always +ve

Cured by ATT

Lichen Scrofulosorum



lichenoid papules

Site ? trunk

Involute after many

months without scars

Tuberculin test ?

strongly +ve

Papulonecrotic Tuberculides
Crops of deep seated papules and nodules
Lesions are capped by pustules; ulcerate

forming crusts

Heal in a few months with scar
New crops keep developing

Tuberculin test strongly +ve

Erythema Nodosum
Crops of indurated very tender,

erythematous deep seated nodules,

which evolve from red to violaceous to


Inspection ? bruise, palpation nodule
Never ulcerates; heal without scarring
Site ? bilateral shins
Constitutional- fever, malaise

Tuberculin test +ve


resolution in 6


Histology ? septal

pannicullitis no


Erythema Induratum

Site- calves in young adult females
Bilaterally symmetrical
Initial develop in cold weather
Subcutaneous nodules and plaques

with gradually involve the overlying

skin with ulceration

Tuberculin test


Ulcers heal

leaving atrophic


Chronic ,


Histological ?

nodular vasculitis


To confirm tuberculosis
A. Biopsy ? caseating granuloma
B. Isolation of M.tuberculosis ?

1.culture of AFB from pus, skin

biopsy specimen

2. PCR
C. Mantoux test

To rule out concomittant tuberculosis

in other organs

1. CXR
2. X-ray joint, bones
3. FNAC ? of enlarged lymph nodes

Differential diagnosis

lupus vulgaris- leishmaniasis, sarcoidosis,

systemic fungal infection, SCC

tuberculosis verrucosa cutis - warts


Standard ATT
Intensive phase ? isoniazid 5mg/kg

For 2 months rifampicin 10mg/ kg

ethambutol 15mg/ kg

pyrazinamide 20mg/kg
Continuous phase - isoniazid 5mg/kg

For 4 months rifampicin 10mg/ kg

Extension ? max. 8 months


This post was last modified on 07 April 2022