Download MBBS Dermatology PPT 4 Cutaneous Tuberculosis Lecture Notes

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






CUTANEOUS

TUBERCULOSIS

ETIOLOGY- Mycobacterium Tuberculosis


PATHOGENESIS- manifestations of lesions depend

on

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

on whether exposure to the bacteria is primary or

secondary

General immunity of the host

2. Route of entry


3. Bacterial load

CLASSIFICATION

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

chancre

Crusts form and edges

become indurated

Regional

lymphadenopathy in

few weeks

Dev. Of immunity

lesion heal to produce

a scar

Warty Tuberculosis/ Tuberculosis Verrucosa

Cutis

Exogenous source
Moderate to high immunity to M.

tuberculosis

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

Colliquativa

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

edge

AFB can be

demonstrated

Orificial Tuberculosis/ Tuberculosis Cutis

Orificialis

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

disease.




Small erythematous

nodules break

down, form round,

shallow, granulating

ulcers covered by

thin crust.

Painful
No tendency to heal

without effective

treatment

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

MUTILATING form




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.


TUBERCULIDES
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

immunity

Tuberculin test always +ve

Cured by ATT

Lichen Scrofulosorum

Tiny<5mm,

perifollicular,

lichenoid papules
Asymptomatic

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

Asymptomatic
Tuberculin test strongly +ve


Erythema Nodosum
Crops of indurated very tender,

erythematous deep seated nodules,

which evolve from red to violaceous to

yellow

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

Tuberculin test +ve
Course-

spontaneous

resolution in 6

weeks

Histology ? septal

pannicullitis no

vasculitis


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

+ve

Ulcers heal

leaving atrophic

scars

Chronic ,

recurrrent

Histological ?

nodular vasculitis


Investigations

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

TREATMENT

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


THANK YOU

This post was last modified on 07 April 2022