Ivory colored hypopigmentation has been frequently observed in morphea and lichen sclerosus et atrophicus, and also seen after phenol peels, dermabrasion, cryosurgery and post-laser resurfacing.

This study was undertaken to investigate the cause of hypopigmentation following autologous suction blister graft (ASBG) in vitiligo patients.

The ivory lesion and contralateral normal skin were collected by punch biopsies. And the tissues were stained with hematoxylin-eosin, Fontana-Masson, Masson's trichrome, Verhoeff-van Gieson, and S-100 protein to compare the differences between two specimens.

H-E and Masson's Trichrome stains showed that compacted hyalinized sclerotic collagens and collapsed, small sized capillaries in the upper dermis were definite in the hypopigmented lesion, whereas normal control sites were unremarkable. Elastic fibers were markedly decreased or fragmented in upper dermis of the hypopigmented lesion. Fontanna-Masson stain identified that the lesional epidermis was more hyperpigmented rather than hypopigmented. S-100 stain showed no differences between hypopigmented and control sites.

The results suggest that the ivory colored hypopigmentation is not caused by the failure of procedure, but by scar formation due to deep freeze; therefore, this kind of complication may be prevented by carefully performing the cryotherapy.