Skin tuberculosis

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I-DEFINITION:

• tuberculosis is all dermatological manifestations due to the presence of TB in the body and especially in the skin.

II– EPIDEMIOLOGY:

1– FREQUENCY:

– rare in Europe and industrial countries, this is due to:

– Improving living conditions, hygiene, and nutrition.

– Vaccination and TB chemotherapy.

– in Algeria, tb is a public health problem that is endemic.

2- PATHOGEN:

– Koch bacillus (BK) is a mycobacteria, immobile, very sensitive to heat but resistant to cold and desiccation,

– coloured red by fuchsin, not discoloured by nitric acid or alcohol (acid-alcoholic-resistant bacillus[BAAR]).

– It is grown in strict aerobics between 35 and 37 degrees Celsius on enriched environments "Lewenstein Jensen" – One distinguishes:

– Mycobacterium tuberculosis hominis or Koch bacillus,

– Mycobacterium tuberculosis bovis, an agent of bovine tuberculosis (involved in 1 to 5% of human TB cases).

III– CLASSIFICATION:

BeYT classification of skin tuberculosis: based on pathophysiological criteria

I- Inoculation tuberculosis (exogenous):

– Tubering chancre

– Wartuted tuberculosis

II- Secondary tuberculosis (endogenous):

– By contiguity: Scrofuloderm

– Self-inoculation: Orificial tuberculosis

III- Blood-borne tuberculosis:

– Vulgar Lupus

– Acute military tuberculosis

– Tuberc plastic gum

IV- Eruptive tuberculosis:

– Lichen scrofulosorum

– Papulous or papulo-necrotic tubercides

– Bazin's indated erythema

– Nodular Vascularitis

I- Inoculation tuberculosis (exogenous):

1- Tubercle Chancre; mutibacillary form

• Secondary to direct skin-mucous inoculation of the bacillus in an unimmunized subject:
• Especially in infants and young children
• After a direct infectious injury: circumcision, traditional surgery, ear piercing, it is rarely a contaminated wound (bites, spitting)
• predominates in the lower limbs, face and orogenetal mucous membranes.
• Incubation:1 to 3 weeks
• a firm erythematovolac nodule, which ulcerates with detachment of the edges and is complicated, in 1 to 2 months, by lymphangitis with satellite poly adenopathy of fistulized evolution
• No general signs
• Evolution: Spontaneous healing sometimes extension of TBC to other organs
• Negative IDR
• Ex direct and cultures allow to find the BK
• Histology finds a nonspecific inflammatory infiltrate rich in PNN , presence of BAAR, granulomatous evolution is only after lymph node damage.

2- Wartish tuberculosis: pauci bacillary form, infrequent

• it results in either:
• the recurrence of The Koch Bacillus in a previously sensitized subject,
• Inoculation is accidental often professional: cattle farmers, slaughterhouse employees, paramedic medical personnel.
• Hard horned nodule that gradually spreads out to form a very limited wart closet surrounded by an inflammatory areola from which deaf pus
• Siege: hands (radial edge), dorsal face of fingers / wrist, peri region and at the buttocks and at the point of inoculation.
• Associated signs: satellite adenopathy, tubercular lymphangitis, damage to the tendons, bones and underlying joints.
• Slow and torpedo evolution
• Untreated: swarming in the vicinity and at a distance
• IDR is positive
• Direct review and often negative cultures
• Histology

– tuberuloid granuloma with casey necrosis

– papillomatosis and acanthosis

– orthokeratosic hyperkeratosis

• Differential diagnosis: skin leishmaniasis, pyodermites, fungi, warts.

Ii. Secondary tuberculosis (endogenous):

1- The scrofuloderm: F .multibacillary

• Makes up more than 50% of all skin TBCs
• Secondary to the extension to the skin of an adenite or osteoarthritis of tuberculosis origin
• Seat: neck, trunk, limbs, spine
• These are dermo-hypodermic nodules, evolving towards softening, fistulization to the skin and ulceration, then healing
• IDR :positive
• The BK is found in the cultivation of the abscess puncture liquid because the ex direct is generally unprofitable
• Radiological and biological explorations allow us to find the original focus.
• Characteristic Histology: Koester tuberuloid follicle with caseous necrosis is re-established at the nodule and softening stage

2- Orificial tuberculosis: F paucibacillary

• Secondary to self-inoculation from pulmonary, laryngeal, digestive and urinary tract.
• Mainly touches the man with evolutionary visceral focus
• subacute periorificial ulcerations (tongue, lips, nostrils, anus, urethra)
• Typical tuber ulcer of the tongue: Unique superficial ulcer, undurable and not infiltrated with irregular edges, the bottom is purulent fibrino, painful.
• associated signs: homolateral inflammatory polyADP.
• evolution: No spontaneous tendency to heal, often with the appearance of small coalescent peripheral exulcerations.
• IDR :positive
• :psositive cultures
• Histology initially a non-specific inflammatory infiltrate with the presence of B.A.A.R., then a pseudo-epitheliomatous hyperplasia forms.
• Differential diagnosis: with sores, mucous plaques of secondary syphilis, sleocellular epithelioma.

III– Hematogenic tuberculosis:

a)– tuber lupus:

• Frequent bacillary pauci form
• Female predominance
• Related to reactivation of visceral TB that is central or rarely progressive
• seat: 80% face, neck, ears, rare on limbs
• Reddish or yellowish placard, soft squamous in relief that slowly spreads with jagged contours, formed by the confluence of lupomes – dermal micronodules – having a yellowish appearance to the so-called "apple jelly" vitropression
• Evolution is slow with ulcerations, atrophic and fibrous scars with evolutionary purple edges
• In the long term, extension can lead to mutilation or even s spinocellular degeneration
• Positive IDR
• Histology agglomeration of tuberculoid granulomas
• Direct examination and culture are often negative
• Differential diagnosis: with sarcoidosis, skin leishmaniasis, tertiary syphilis

b)– Acute military tuberculosis:

• it results in either:
• blood-borne spread from a visceral focus, most often pulmonary or
• Occurs during severe first infection on immunosuppressed terrain
• Malnourished child, elderly
• Bluish papules, scattered necrotic hemorrhagic vesicles
• Alteration of the general state
• Frequently associated with pulmonary miliary, meningeal
• Eye background: Bouchut retinal tubers
• Negative IDR
• Ex direct finds the BK
• Evolution is often fatal

c)– Tuberculosis gum:

Tuberculosis gums:

• immunosuppressed, malnourished.
• seat: especially the lower limbs.
• appearance: cold abscesses or firm dermohypodermal nodules that soften and then ulcerate.
• The progression is slow (several months) towards a fibrous scar
• bacteriological examinations (Ziehl-Neelsen and culture) can objectify the BK.
• histology: the tuberculoid follicle of Koster is found before the stage of ulceration.

IV- Eruptive tuberculosis:

Skin manifestations involving immunological phenomena

1- Lichen scrofulosum

• Rare, child
• Micro pink papules, firm, shiny cluster in granite cupboards
• Trunk, limbs, upper lips
• IDR

2- Tuberculides papulo necrotic

• Dark, hard, sometimes pustular red papules in places or necrotic.
• Faces of extension of the limbs, dorsal face of the hands, feet, buttocks, lumbar region.
• IDRT always positive.
• Histology: tuberuloid granuloma with case necrosis.
• Bacteriology always negative.
• Differential diagnosis: with necrotic acne, necrotic syphilids, prurigo, boils.

3- Bazin's indated erythema

• Predominant asymmetric hypodermitis flare-ups to lower limbs
• Predominates in obese women with venous insufficiency
• Purple and painful inflammatory nodules or closets with chronic evolution
• IDR

4- knotty rash

• Manifestation of the first TB infection
• Acute nodular hypodermitis, performing painful hot red inflammatory nodos
• Leg extension faces
• Fever, arthralgia and altered general condition

V- skin manifestations of BCG:

On the BCG website you can have

• Ulceration not only scarring several months of evolution
• Pustular reaction
• Nodule under skin evolving towards absedation
• Rarely diffuse manifestations:papulonecrotic tuberculides,EN,nodular vascularitis

IV- POSITIVE DIAGNOSTIC ELEMENTS:

– it is held on a bundle of arguments.

1/ Presumption elements:

'Anamnesis':

– Tb screening.

– history or coexistence of visceral TB lesions.

Biology:

– FNS: hyperleucocytosis with hyper lymphocytosis.

– IDR: tubercina, uses purified tubercina

– Injection of 10 IU of tubercle intradermal, on the ant side of the forearm.

– Play after 72 hours, measuring the diameter of the induration

2/ Elements of certainty:

A– bacteriological:

– this is the highlighting of the BK.

– the sample: on a skin caseous fireplace, puncture of an adenopathy, biopsy part, serouss.

1- DIRECT EXAMEN: after coloring ZIEL NELSEN, looking for BAAR

2- CULTURE on the middle of lovenstein

– For the identification of the species and the development of the antibiotic:

– the multiplication of Koch bacillus (division time – 20 hours) requiring an average growing time of 28 days, and 42 days.

B- histology:

– The characteristic but non-specific histological element of tuberculosis is the Koester follicle

C- "PCR" genetic amplification methods:

– their interest is in paucibacillary forms such as vulgar lupus, or reactionary states (erythema, indurated BAZIN), but however it lacks specificity and sensitivity,

VI– TREATMENT:

Anti-TB chemotherapy (Rifampicin,Isoniaside,Ethambutol,Pyrazinamide)

• Triple for 2 months
• Double for 4 months
• Depends on the clinical form
• Oral ANTI-TB should be administered in a single morning dose on an empty date 1/2 hour before breakfast.
• Patients who have had a major side effect to one of the products may use separate molecules.
• Rimifon alone has a dose of 5 mg/kg/J for 6 months may be sufficient in the treatment of BCG complications

VII- PROPHYLAXIS:

• It is based on vaccination with BCG, a vaccine made up of live attenuated bacillus,
• early detection and treatment of multibacillary forms to prevent contagion,
• raising the overall socio-economic level, allowing for better hygiene and nutrition conditions.