Coal Tar

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Coal tar therapy has been used for well over a century in dermatology.

It is a topical treatment mostly used for acute scalp psoriasis. It has anti-inflammatory properties that are useful in chronic plaque psoriasis; it also has antiscaling properties. Crude coal tar (coal tar, BP) is the most effective form, typically in a concentration of 1 to 10% in a soft paraffin base, but few outpatients tolerate the smell and mess.

Cleaner extracts of coal tar included in proprietary preparations, are more practicable for home use but they are less effective and improvement takes longer.

Contact of coal tar products with normal skin is not normally harmful and they can be used for widespread small lesions; however, irritation, contact allergy, and sterile folliculitis can occur. The milder tar extracts can be used on the face and flexures. Tar baths and tar shampoos are also helpful.

Coal tar has also been used in combination with Ultraviolet B light in hospitals - Goeckerman method.

How does it work?
Coal tar is mildly antiseptic and relieves itching. It also acts as a keratolytic, which works to break down a protein which forms part of the skin structure called keratin. Skin thickening occurs due to the deposition of keratin. Coal tar helps to reduce the excessive hardening, thickening and scaling of the skin

How to use coal tar on the scalp
Make several partings in your hair. Apply the treatment along the partings. Start on one side of the head and move methodically over the scalp to avoid missing an area.

Always read the information leaflet provided with the medicine or consult your doctor or pharmacist.

Cautions
When using coal tar avoid eyes, mucosa, genital or rectal areas, and broken or inflamed skin; use suitable chemical protection gloves for extemporaneous preparation. coal tar should not be used in sore, acute, or pustular psoriasis or in presence of infection. Coal Tar will stain jewellery - permanently - even gold. Take care to remove all jewellery before using coal tar products.

Precautions
Avoid exposure to sunlight or sunlamps while using this medicine, as it increases the sensitivity of your skin. If exposure to sunlight cannot be avoided, use protective measures such as sun-creams or protective clothing. This medicine will stain skin, hair and fabric. Avoid contact with eyes, mucous membranes, genital and rectal areas. This preparation is for external use only. Avoid contact with eyes, eyelids and all other mucosal surfaces Not for use with acute psoriasis

Side effects
Some common side effects could include Abnormal reaction of the skin to light, usually a rash (photosensitivity) Staining of skin and clothes Skin irritation The side effects listed above may not include all of the side effects reported by the drug's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

Tar: Some fascinating facts
Did you know...

  • Tar is one of the most ancient skin treatments still in use; it has been used to treat skin problems for an amazing 2,000 years (1)
  • Crude coal tar is thought to contain around 10,000 different substances; only half of these have been properly identified(1)
  • A bituminous medical tar can be obtained from rock formations containing the fossilised remains of fish!(1)
  • Coal tar is made by heating coal in the absence of air at temperatures of up to an immense 1200°C (2) - that’s around five times hotter than the average kitchen oven
  • Coal tar can itself be heated to produce different types of oil; a residual by-product of this is pitch - the substance used in roadmaking (1)

References
(1.)Lin AN, Moses K. Tar revisited (Review). Int Jnl Derm 1985;24:216-218
(2.) Comaish JS. Tar and related compounds in the therapy of psoriasis. Clin Exp Derm 1981;6:639-645

Tar based products include: