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].