Ordinary scaly psoriasis and a form of pustular psoriasis can affect
the hands and the feet. It isusually the palms and soles that are
involved. Although these may be the only sites affected, the resultant
disability can be quite out of proportion to the extent of the disease.
The horny layer of the palms and soles needs to be tough yet elastic
for proper function. When it is abnormal, as in psoriasis, it tends
to crack. The cracks that form can become inflamed and very painful,
just as in dermatitis. This discomfort can prevent ordinary use
of the hands and may even make walking difficult.
to appear at the sites of injury. This is known as the isomorphic
response (the Koebner phenomenon). For this reason attacks of psoriasis
can be precipitated by tough manual work. Similarly, patches of
psoriasis can be made worse if subjected to perpetual minor irritation.
Patients differ in the way that they react to injury, and so advice
has to be tailored to the individual.
Pustular psoriasis affecting the sole.
Nail pitting in psoriasis is faily common.
If the nails are particularly
badly involved other problems can arise. The pitting and discolouration
are unsightly but it is the separation of nail plate from nail bed
(onycholysis) that causes most complaints and can make some jobs
very difficult. Needlework or work requiring delicate manipulations
such as in the electronics industry are two such examples. Office
work, particularly typing, can also be a trial if there is extensive
involvement of the fingernails.
When psoriasis affects the hands
there is also the problem of the general public's reaction to its
appearance. I have known several waiters who virtually have had
to look for other types of work because their employers have said
that they could not serve at table while their hands were affected.
It must also be remembered that ointment or cream treatments become
difficult for those who work with their hands. Most topical applications
are in some degree greasy and will tend to rub off and soil paper
or other materials that need to be handled.