Stephen A. Estes

Survival and infestivity of Sarcoptes scabiei var. canis and var. hominis

Sarcoptes scabiei var. canis served as a suitable model for the study of S. scabiei var. hominis survival. S. scabiei var. canis and var. hominis mites were found to survive off the host for 24 to 36 hours at room conditions (21 degrees C and 40% to 80% relative humidity [RH]), and the canine variety survived 19 days at 10 degrees C and 97% RH. Female mites survived decidedly longer than male mites at comparable conditions. Generally, higher RH values and lower temperatures favored survival, whereas higher temperature and lower RH led to early death. Most canine scabies mites that were held off the host for 36 hours at 75% RH and 22 degrees to 24 degrees C remained infective and penetrated when returned to the host. Live mites of the human variety that were recovered from bed linen slept on by infested patients would also penetrate a host after being held off a host for 96 hours in alternating 12-hour periods of room conditions and refrigeration. Penetration required less than 30 minutes for all life stages of both varieties, and it was accomplished by a mite secretion that dissolved the host tissue. Dislodged mites, particularly those in close proximity to the source, can be a likely source of infestation.

Cross infestivity of Sarcoptes scabiei

Sarcoptes scabiei var. canis was successfully transferred from the dog to New Zealand White Rabbits, Oryctologus cuniculus. Natural and experimental transfers were accomplished between rabbits. The dog strain transferred to rabbits showed no morphologic changes and was readily transferred back to dogs. Experimental transfer of var. canis to guinea pigs and pigs resulted in only temporary infestation. Attempts to infest haired and hairless mice, thymus-deficient (nude) mice, and rats were unsuccessful. The unsuccessful or transient nature of cross-infestations between some host species and complete cross-infestation in others leads to the conclusion that all S. scabiei varieties are not host-specific but that they do possess some degree of host preference and that physiologic differences between varieties exist.

Delayed pressure urticaria: An investigation of some parameters of lesion induction

Two patients with delayed pressure urticaria were studied to define some of the physical parameters related to experimental lesion induction using a pressure-testing device. Graded pressures from 48 to 234 gm/mm2 were applied for 1 to 180 seconds on several anatomic areas. Experimentally induced lesions were symptomatically, clinically, and histologically identical to spontaneous wheals and reached a maximum size 9 hours after the stimulus. The threshold response found was related to the amount of pressure, the duration it was applied, and the anatomic area tested. Sites that previously reacted to pressure were refractory to additional stimuli for at least 24 to 48 hours. The mediator for delayed pressure urticaria remains unknown, and some patients do not respond to oral corticosteroids.

Genital benign chronic pemphigus (Hailey-Hailey disease) presenting as condylomas

BACKGROUND Genital lesion sof benign chronic pemphigus (FBCP)(Hailey-Hailey disease) may present as verrucous papules. Genital warts and papular acantholytic dyskeratosis of the genitalia may be considered in the differential diagnosis. OBJECTIVE Our purpose was to describe the clinical characteristics and histologic features of verrucous anogenital FBCP. METHODS Six patients, five women and one man, with verrucous anogenital lesions of FBCP, initially diagnosed as warts, were examined and biopsy specimens were evaluated histologically. RESULTS The lesions were located exclusively in the perineal and perianal regions with axillary involvement in one case. Family history was negative in three of the six cases. Histologic examination confirmed the diagnosis of FBCP but was significant for the absence of crusts and the presence of only minimal inflammation. CONCLUSION Our cases and the literature are reviewed with the conclusion that all verrucoid genital lesions with the histologic characteristics of Hailey-Hailey disease may represent FBCP.

Host-seeking behavior of Sarcoptes scabiei

Sarcoptes scabiei mites perceive specific host stimuli and are attracted to the host. Mites dislodged from the host respond to both host odor and a thermal stimulus and seek its source. The response to thermal and host odor stimuli are independent. Mites in close proximity to the body respond to both stimuli and show no preference for either. At greater distances from the host, odor is the more important stimulus.

Pemphigus vulgaris involving the esophagus: a case report and review of the literature

SummaryA case of pemphigus vulgaris confined to the oral cavity, larynx, and hypopharynx for two years with subsequent involvement of the entire esophagus is presented. Histopathology and direct immunofluorescence of the esophagus confirmed the diagnosis.