Cryotherapy for Psoriasis

Cryotherapy has been reported in an uncon
trolled study' to be effective in the treatment of
patients with psoriasis- We evaluated the role
of crvotherapy in the treatment of small psoriatic plaques.

Subjects and Methods. Nine patients, aged 35 to 81 years, with clinically diagnosed small plaque psoriasis (plaque sizes 0-5 cm) consented to participate in this study. Two plaques of approximately the same size and severity, in symmetrical areas of the body. were randomly assigned as treatment (crvotherapy) and control sites. The entire crvotherapy site was frozen homogeneously with a liq¬uid nitrogen cryostat (type B tip. Cryogun. Brymill Cor¬poration, Vernon, Conn), No other treatments were ap¬plied- Two to 3 days following treatment, blister formation was assessed. The lesions were reevaluated at 2, 4. and 12 weeks after treatment. A lesion severity score was de-fined as the sum of 3 parameters: erythema, thickness, and scaliness, each rated from 0 (none) to 4 (severe)- All lesions were evaluated and measured by a single re-searcher (K.N.) using perpendicular dimensions corre¬sponding to length and width

Results, The average freezing time for all treated sites was 12 s/cm2, with times ranging from 5 to 15 seconds, All pa¬tients had a blister at the crvotherapy site at the 2-day follow-up visit. The percentage of resolution was calculated for the crvotherapy sites based on the change in seventy scores during the 12-week study period (Figure 1)_ five patients had complete resolution (100%), 2 had a substantial reso¬lution (75% and 80%), 1 showed a mild to moderate reso¬lution (33%), and 1 had no resolution (0%) of the treated sites. The mean severity score of the crvotherapy sites decreased significantly, from 6.7 to 1.4 (P<.001), while con¬trol sites did not change significantly, from 7.0 to 7.1 (P<40), each site either not changing or worsening (Figure 2)- Calculations were performed on raw. unal¬tered. unaveraged data analyzed using a paired Student t test. Differences were considered statistically significant if valid at the 95% confidence interval, P<.05.
Three of the 5 patients with complete lesion reso¬lution developed hypopigmentation and atrophy at the treated sites- One patient developed a mild secondary in¬fection following cryotherapv. requiring treatment with oral cephalexin hydrochloride.

Comment. Cryotherapy to treat psoriasis was first evalu¬ated by Scoggins,' who reported a response rate of 67% to 80% in 35 patients with more than 220 plaques. Reso¬lution was achieved by freezing the entire plaque to the point of blister induction However, to our knowledge, ours is the first controlled study of this subject.

Mechanisms of cryotherapv mediated resolution of treated plaques may include normal reepithelialization fol¬lowing physical destruction of psoriatic lesions, shortening of elongated dermal papillae.2 reverse Kobner phenomenon (appearance of psoriasis in nonlesional skin following skin injury),3 and the creation of a scarred or altered dermis

Keyvan Noun, MD
Timothy K. Chartier, MD William H. Eaglstein, MD Miami, Florida
J. Richard Taylor, MD Dermatology Services
Veterans Affairs Medical Center Miami, FL 33125

This study was supported in part by the Dermatology Foundation of Miami.
 
'ARCH DERMATOLOGY/VOL 133, DEC 1997
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