ANAND

Coal TarA short talk

Tar -3 Types

• Wood Tar:- Juniper tar, Pine tar ,Birch tar• Shale Tar:- Icthammol (Icthyol)• Coal Tar:- Liquor picis carbonis(LCD)

Wood Tar

• Distillation of wood under controlled conditions• Most commonly from juniper (oil of cade)• Also be derived from Peech, birch & pine• Can be added to peanut oil or other bases• Typically used to treat scalp psoriasis• Contact sensitivity been reported• Not photosensitive

Shale tar

• From sedimentary rock ( Fossilised fish)• Also known as bituminous tar• Eg:-Icthammol/ Icthyol (It has sulphr 10%)• Antiseptic & anti inflammatory action• Less effective than coal tar• Not photsensitive

Coal Tar

COAL (1Ton)

Solids(70%)Coke breeze

GasCoke gas

LiquidsTar(10 gallons)

Amm sulphate & liquor Light oil

Coke Oven

Coal Tar

• Coal tar has been used to treat inflammatory dermatoses for up to 2 millennia

• 2000 yrs old(Asphalt used in 20 AD)• By product of dry distillation of Coal heated in

absence of Oxygen• Used primarily to treat psoriasis

Coal Tar

• Thick Brown black Viscous liquid• Slightly water soluble• Specific activity of each constituents is

unknown(400/10,000 been identified)• Only 55% of its contents• Pharmacology of coal tar has not been

standardised

• Aromatic ,Complex substance• Crude coal tar -48% HC, 42% Carbon & 10 % Water• 02-10%-Middle oil-Phenol,cresol,naphthalene• 02-08%-Light oil-Benzene,Toluene• 16-20%-Anthracene oil• 50%-Pitch• Coal Pitch-Photosensitiser (330-550nm)-(VL &UV A)

0.5-10% -In a broad array of vehicles

• Liquor carbonis detergens:- 20g Coal Tar with 100ml Alcohol & emulsifying with

5g of Tween 80• Most often obtained in solution form (0.1 to 20%) and mixed with ingredients, such as salicylic acid & sulphur to make lotions, creams, ointments & shampoos

(1884-1954)

• Goeckermans regimen- 1925• 2-6 % CT in petrolatum for 2-24 hrs• Wiped off with mineral oil …..followed by UV light

• (Decreased blood flow in psoriatic lesions of patients treated with Goeckerman regime)

• Isoquinoline may be the antipsoriatic constituent in Coal tar

Mechanism of action

• It depresses epidermal DNA synthesis• Reducing mitotic activity in basal layers of

epidermis• Initial transient hyperplasia followed by 20%

reduction in epidermal thickness after 40 days-On application to the skin

Other Actions

• Anti inflammatory• Anti-infective• Antipruritic • Decreases Sebum secretion• Photosensitizing & Vasoconstrictive effects

How to use coal tar

• Apply at bedtime to avoid problem of smell & staining during day

• Cover with bandages to stay in place & prevent staining.• Plastic wrap may cause irritation & infection• On scalp, apply with a downward stroke in the direction of

hair growth• Do not apply to infected, raw or oozing areas of the skin • After applying coal tar , protect the treated area from

direct sunlight & do not use a sunlamp• Avoid mucosa• Cautious use over groin & rectal region

Coal Tar Bath

• Adults:-150-200 litres• Children :-50-60 litres of water• 100ml of coal tar solution should be added to

a standard bath of warm water• Soak in this water for five minutes then pat

the skin dry

Indications

• Scalp Psoriasis• Plaque psoriasis• Atopic dermatitis• Discoid eczema• Seborrheic dermatitis• Tufted hair folliculitis• Palmoplantar pustulosis

• Application of coal tar provides local relief, while softening dry skin and peeling off excessively hard, scaly and roughened skin.

• Coal tar derivatives like acetanilide, phenacetin, & paracetamol (acetaminophen)

are pain killers• Paracetamol is the only coal-tar derived

analgesic still in use today

• Systemic adverse effects -uncommon, whereas local adverse effects are present

• Newer formulations, however, might be better tolerated

Disadvantages & Adverse effects

• Smell• Appearance• Staining of clothes• Acneiform eruptions• Contact dermatitis• Folliculitis• Skin cancer risk –Not significant

(Anthracene,Benzpyrene)

• Stinging• Burning sensation• Atrophy• Telengiectasias• Pigmentation(Melanoses)• Exfoliative dermatitis• Keratoacanthomas• Papilloma• Avoided in pregnancy & Lactation (Category C)

Complications

• Coal Tar Acne:- Comedonal type Around eyes & malar region Clears rapidly after the exposure ceases

• “Tar smarts” (Skin pain) & Erythema following exposure to UVA

• The dirtier , blacker & smellier the coaltar fraction , the more effective it is in psoriasis

• Salicylic acid is often added -Enhances coal tar absorption by its keratolytic effect

• Allergy for wood tar in patch test –Indicator of Perfume allergy

Atopic dermatitis

• Before the advent of Corticosteroids• Preparations containing Coal tar & icthammol

used in maintaining pt with lichenification• 1-10% coal tar solution in an oint /cream base

is preferred to crude coal tar• Icthammol can be used with plastic bandages

Seborrheic dermatitits-Scalp

• Normalises epidermal differentiation• Decreases scaling• Found to be useful with Zinc pyrithione• Applied and kept for 30 min and washed off

Thank You