Journal of the American Academy of Dermatology
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J. Am. Acad. Dermatol. · Jan 1985
Case ReportsTinea versicolor: a light and electron microscopic study of hyperpigmented skin.
Hyperpigmentation in lesions of tinea versicolor has previously been reported to be a result of the effects of the fungus Pityrosporon orbiculare on melanosome formation and distribution. Examination of biopsy specimens from lesions of hyperpigmented tinea versicolor involving vitiliginous skin reveals an absence of melanosomes and melanocytes. Reddish-tan and fawn-colored hyperpigmentation in tinea versicolor of this type is not due to melanin pigment. The possible nature of the pigmentation that delineates hyperpigmented tinea versicolor from normal skin is discussed.
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Meralgia paresthetica has been described as a common affliction of the lateral femoral cutaneous nerve, creating the symptoms of numbness, tingling, and paresthesias in the overlying areas of the lateral and anterior thigh. It is second only to sciatica in peripheral nerve diseases of the lower extremity. We present two patients with classic symptoms of meralgia paresthetica and nonscarring alopecia overlying and demarcating the areas of paresthesias. Meralgia paresthetica should be included in the differential diagnosis of localized alopecia of the anterior or lateral thigh.
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Postoperative localized alopecia has been reported most commonly after certain gynecologic and open heart surgery procedures, the likelihood of hair loss and the chance of permanence correlating with the length of the anesthesia and the intubation. Some cases of pressure-induced alopecia have been described after prolonged coma from other causes. Coma blisters have been reported after drug overdoses, but clinically similar blisters (not tested by biopsy) have been seen in other cases of coma. We present three cases of postoperative (pressure) alopecia and propose that both coma blisters and postoperative alopecia arise from the same phenomenon--probably pressure-induced ischemia.