Discussion:
A combination of UVB phototherapy, cryotherapy, and intralesional
corticosteroids was used to treat refractory prurigo nodularis (PN).
Despite known individual effectiveness for PN, clinical studies have
not, to the knowledge of the authors, evaluated the benefit of
combination therapy with these agents. A prospective, open label trial
noted marked response of PN to 32 UVB courses [5]. Our patient
responded to fewer sessions of UVB therapy, possibly due to additional
agents. The use of excimer UVB and psoralen UVA (PUVA) for PN is
supported by previous literature [6,7]. While our patient responded
to UVB therapy alone, these may be beneficial should relapse occur.
Although excimer technology may improve healing and limit adverse
effects, it is not available in all centers.
Reports of cryotherapy for prurigo nodularis exist, although limited
[8,9]. Cryotherapy durations from 5-30 seconds may be
beneficial[8,9]. Hypopigmentation is expected after treatment and
may offset the hyperpigmentation of PN lesions [9]. Patients should
be counselled on blister formation, which is common following
cryotherapy.
The immunosuppressive action of corticosteroids is well-known, although
their systemic use often leads to adverse effects, similar to our
patient. High-dose topical corticosteroids and intralesional injection
have a highly effective locally at PN lesions, and sparing many of the
adverse effects of systemic corticosteroids [10].