Photochemotherapycombining long-wave ultraviolet A
radiation with a psoralen (PUVA) is available in specialist
centres under the supervision of a dermatologist. The
psoralen, which enhances the effect of irradiation, is
administered either by mouth or topically. PUVA is effective
in most forms of psoriasis, including thelocalised
palmoplantar pustular psoriasis. Early adverse effects include
phototoxicity and pruritus. Higher cumulative doses
exaggerate skin ageing, increase the risk of dysplastic and
neoplastic skin lesions especially squamous cancer, and pose
a theoretical risk of cataracts.
Phototherapy combined with coal tar, dithranol, topical
vitamin D or vitamin D analogues, or oral acitretin, allows
reduction of the cumulative dose of phototherapy required
to treat psoriasis.
Systemic treatment
Systemic treatment is required for severe, resistant, unstable
or complicated forms of psoriasis, and it should be initiated
only under specialist supervision. Systemic drugs for
psoriasis include acitretin and drugs that affect the immune
response (see Eczema and psoriasis, drugs affecting the
immune response below).
Acitretin p. 749 , a metabolite of etretinate, is a retinoid
(vitamin A derivative); it is prescribed by specialists. The
main indication of acitretin is severe psoriasis resistant to
other forms of therapy. It is also used in disorders of
keratinisation such as severeDarier’s disease(keratosis
follicularis), and some forms ofichthyosis. Although a
minority of cases of psoriasis respond well to acitretin alone,
it is only moderately effective in many cases; adverse effects
are a limiting factor. A therapeutic effect occurs after 2 to
4 weeks and the maximum benefit after 4 months.
Consideration should be given to stopping acitretin if the
response is inadequate after 4 months at the optimum dose.
Continuous treatment for longer than 6 months is not
usually necessary in psoriasis. However, some patients,
particularly those with severe ichthyosis, may benefit from
longer treatment, provided that the lowest effective dose is
used, patients are monitored carefully for adverse effects,
and the need for treatment is reviewed regularly. Topical
preparations containing keratolytics should normally be
stopped before administration of acitretin. Liberal use of
emollients should be encouraged and topical corticosteroids
can be continued if necessary.
Acitretin is teratogenic; in females of child-bearing age,
the possibility of pregnancy must be excluded before
treatment and effective contraception must be used during
treatment and for at least 3 years afterwards (oral
progestogen-only contraceptives not considered effective).
Topical treatment
The vitamin D and analogues, calcipotriol p. 750 , calcitriol
p. 631 , and tacalcitol p. 751 are used for the management of
plaque psoriasis. They should be avoided by those with
calcium metabolism disorders, and used with caution in
generalised pustular or erythrodermic exfoliative psoriasis
(enhanced risk of hypercalcaemia).Eczema and psoriasis, drugs
affecting the immune response
Overview
Drugs affecting the immune response are used for eczema or
psoriasis. Pimecrolimus p. 747 by topical application is
licensed formild to moderate atopic eczema. Tacrolimus
p. 522 is licensed for topical use inmoderate to severe atopic
eczema. Both are drugs whose long-term safety is still being
evaluated and they should not usually be consideredfirst-
line treatment unless there is a specific reason to avoid or
reduce the use of topical corticosteroids. Treatment withtopical pimecrolimus or topical tacrolimus should be
initiated only by prescribers experienced in treating atopic
eczema.
Topical corticosteroids have a role in eczema and a limited
role in psoriasis. A systemic corticosteroid such as
prednisolone p. 442 may be used in severe refractory eczema.
Systemic drugs acting on the immune system are generally
used byspecialistsin a hospital setting.
Ciclosporin p. 519 by mouth can be used forsevere
psoriasisand forsevere eczema. Azathioprine p. 518 or
mycophenolate mofetil p. 527 are also used for severe
refractory eczema in children.
Methotrexate p. 543 can be used forsevere resistant
psoriasis; the dose is givenonce weeklyand adjusted
according to severity of the condition and haematological
and biochemical measurements. Folic acid p. 574 should be
given to reduce the possibility of methotrexate toxicity
[unlicensed indication]. Folic acid can be given once weekly
on a different day to the methotrexate; alternative regimens
may be used in some settings.
Etanercept p.^643 (a cytokine modulator) is licensed in
children over 6 years of age for the treatment ofsevere plaque
psoriasisthat is inadequately controlled by other systemic
treatments and photochemotherapy, or when these other
treatments cannot be used because of intolerance or contra-
indications.
Adalimumab p. 642 (a cytokine modulator) is licensed in
children over 4 years for the treatment ofsevere chronic
plaque psoriasisthat is inadequately controlled by other
topical treatments and phototherapies, or when these
treatments are inappropriate.CORTICOSTEROIDS
Topical corticosteroids
Overview
Topical corticosteroids are used for the treatment of
inflammatory conditions of the skin (other than those
arising from an infection), particularly eczema, contact
dermatitis, insect stings, and eczema of scabies.
Corticosteroids suppress the inflammatory reaction during
use; they are not curative and on discontinuation a rebound
exacerbation of the condition may occur. They are generally
used to relieve symptoms and suppress signs of the disorder
when other measures such as emollients are ineffective.
Children, especially infants, are particularly susceptible to
side-effects. However, concern about the safety of topical
corticosteroids in children should not result in the child
being undertreated. The aim is to control the condition as
well as possible; inadequate treatment will perpetuate the
condition. Carers of young children should be advised that
treatment shouldnotnecessarily be reserved to‘treat only
the worst areas’and they may need to be advised that
patient information leaflets may contain inappropriate
advice for the child’s condition.
In an acuteflare-up of atopic eczema, it may be
appropriate to use more potent formulations of topical
corticosteroids for a short period to regain control of the
condition.
Topical corticosteroids are not recommended in the
routine treatment of urticaria; treatment should only be
initiated and supervised by a specialist. Topical
corticosteroids may worsen ulcerated or secondarily infected
lesions. They should not be used indiscriminately in pruritus
(where they will only benefitifinflammation is causing the
itch) and arenotrecommended for acne vulgaris.
Systemic or very potent topical corticosteroids should be
avoided or given only under specialist supervision in
psoriasis because, although they may suppress the psoriasis
in the short term, relapse or vigorous rebound occurs on732 Inflammatory skin conditions BNFC 2018 – 2019
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