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Skin Conditions And The Pharmaceutical Industry
A
brief history of medicines discovery
In the early nineteenth century, the pharmaceutical
industry did not exist and there were no man-made medicines
for treating skin disorders: People had to turn to
nature. Even today’s herbalist books list plants
such as figwort, mountain grape, red clover and chickweed,
useful in herbal tea, or creams for all three of the
conditions considered in this booklet. Burdock and
comfrey are also claimed to be of value in eczema and
psoriasis. One animal product may also have been used
as an early emollient. That was lanolin, a waxy secretion
of sheep sebaceous glands that waterproofs their wool.
| TYPE OF MEDICINE |
Lotions, pastes, creams, gels and
ointments that may be applied
to the skin in: |
Medicines that may be prescribed
for taking by mouth in |
| |
Acne |
Eczema |
Psoriasis |
Acne |
Eczema |
Psoriasis |
| Corticorsteroids |
|
√ |
√ |
|
|
|
| Anti-androgens |
|
|
|
√
(females only) |
|
|
| Antiseptics |
√ |
√
(infected) |
|
|
|
|
| Antibiotics for
bacterial infection |
√ |
√
(infected) |
|
√ |
|
|
| Medicines that
break down keratin |
√ |
√ |
|
|
|
|
| Dithranol |
|
|
√ |
|
|
|
| Medicines related to
vitamin D |
|
|
√ |
|
|
|
| Medicines related to
vitamin A |
√ |
|
√ |
√ |
|
√ |
| Cytotoxic agents |
|
|
|
|
√ |
√ |
| Immunodulators |
|
√ |
|
|
|
|
| Immunosuppressives |
|
|
|
|
√ |
√ |
| Anti-itch (pruritus) |
|
√ |
√ |
|
√ |
|
| New biologicals |
|
|
|
|
|
|
By the mid-1800s, the Industrial Revolution was
in full swing and coal tar, a liquid waste product
arising from the heating of coal at high temperatures,
was becoming an industrial nuisance, as little of
it had a use. However, from about 1855 onwards, chemists
were able to devise methods for cleaning coal tar,
ultimately giving rise to semi-purified distillations
that were found to be beneficial in some skin disorders.
From then on, there has been steady progress and
many new classes of medicines have been identified,
some of which have use in more than one skin condition.
The first scientific reference to a specific psoriasis
treatment was made in 1876 by Dr Balmanno Squire.
He described a patient who successfully used goa
powder (an extract of the Brazilian araroba tree)
to treat a lesion he thought was ringworm. In fact,
it was psoriasis. Years later, the active ingredient
was shown to be chrysarobine, an agent related
to anthralin (dithranol). But it was still 40 years
before anthralin was synthesised and shown to be
an effective treatment for psoriasis. Coal tar
preparations and anthralin remained the mainstay
of treatment for the next hundred years, and are
still in use today.
A major step forward occurred in the mid-1930s,
as chemists began to isolate human hormones from
organs such as the adrenal gland. They mostly
belonged to a chemical class that we now call the
corticosteroids. Biological studies in the 1940s
showed that they had a wide range of effects in the
human body and in 1952, the first clinically useful
topical steroid derivative was introduced for the
treatment of skin complaints. These had weak potency
and had to be applied under dressings. Today’s steroids have a range of potencies
and are available for both eczema and psoriasis.
From the 1950s on, there has been a slow but
steady advance in new medicines discovery.
The era of antibiotics began in earnest in the 1950s,
thus providing treatments for acne. The activity
of topical vitamin A in acne was observed in
1960. Synthetic derivatives of this have given
rise to the retinoid family of medicines, with
applications in both acne and psoriasis. This
was followed in 1985 by the discovery of active
chemicals related to vitamin D, leading to
anti-psoriasis medicines such as calcipotriol, tacalcitol
and calcitriol. Meanwhile, between 1950 and 1990,
medicines that act on the immune system, such
as methotrexate, azathioprine and cyclosporin
have found application in more serious disease.
In the past decade, scientists at last began
to unravel the complex events that are taking
place in the skin of people with acne, eczema
and psoriasis. As a result, the new millennium
opened with the availability of a new generation
of medicines, the biologicals. These carry
a message of hope in moderate and severe
psoriasis, representing the fruition of 50 years
of research and the timely convergence of many branches
of science. For the first time we can begin
to say why the disorders are occurring, rather
than simply describing the structural changes
in
the skin.
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