The histopathologic diagnosis of post-operative alopecia

Pressure alopecias: A review

Pressure-induced alopecias (PAs) are an infrequent group of scarring and nonscarring alopecias that occur after ischemic obstruction of capillaries that leads to circumscribed areas of hair loss. Initially described after prolonged surgeries or immobilization, type 1 PA occurs after sustained external pressure to the skin, mainly the scalp prominences. Alopecia induced by cosmetic procedures, referred in this review as type 2 PA, is reported with increased frequency in literature and predominantly emerges from pressure exerted by the volume of injectables. It is important to differentiate type 2 PA from vascular occlusion-induced alopecia because they represent distinct entities. Clinically, PA may present with erythema, swelling, and tenderness; however, alopecia might be the sole manifestation. Crusts and ulceration are associated with a worse outcome and a higher risk of scarring alopecia. Prompt diagnosis is paramount to prevent complications. Trichoscopy, although considered nonspecific, may provide relevant clues for an accurate diagnosis. Hair regrows in most cases, but prognosis depends on ischemia severity and timely treatment with reperfusion therapies or mobilization. Treatment of hair loss is usually not necessary because the disease in most cases is self-limited and reversible. The role of topical minoxidil and corticosteroids remains unknown.

Pressure-Induced Alopecia: Presence of Thin Hairs as a Trichoscopic Clue for the Diagnosis

Pressure-induced alopecia (PA) is an unusual pattern of circumscribed hair loss that occurs after ischemic changes on the scalp. Trichoscopic findings described in the literature are scarce, nonspecific, and include black dots, broken hairs, circle hairs, and erythema. However, we report 3 cases of PA in which trichoscopy also showed many vellus and thin hairs. Possibly, the maintenance of these hair shafts may be explained by the more superficial insertion of their bulbs on the skin and/or their lower metabolic rates, making them suffer less from local hypoxia. Therefore, the authors suggest that these relevant signs should be added as a clue for the diagnosis of PA in doubtful cases.

A unique case of pressure-induced alopecia following EEG monitoring

We report a unique case of pressure-induced alopecia (PIA) in a 11-year-old boy following the use of electroencephalogram (EEG) electrodes on the scalp for 4 days. PIA is caused by localized ischemia leading to vascular congestion and discrete, often circumscribed patches of hair loss within 3-28 days of pressure interface. The synchronous conversion of follicles from anagen to catagen or telogen phase is the most distinctive finding of PIA. PIA is a nonscarring alopecia which often resolves over time without treatment.

Radiation-Induced Alopecia after Endovascular Embolization under Fluoroscopy

Radiation-induced alopecia after fluoroscopically guided procedures is becoming more common due to an increasing use of endovascular procedures. It is characterized by geometric shapes of nonscarring alopecia related to the area of radiation. We report a case of a 46-year-old man presenting with asymptomatic, sharply demarcated rectangular, nonscarring alopecic patch on the occipital scalp following cerebral angiography with fistula embolization under fluoroscopy. His presentations were compatible with radiation-induced alopecia. Herein, we also report a novel scalp dermoscopic finding of blue-grey dots in a target pattern around yellow dots and follicles, which we detected in the lesion of radiation-induced alopecia.