Frontal fibrosing alopecia. Clinical, quality of life and histopathologic analyses

Laburpena

Frontal fibrosing alopecia (FFA) is a scarring alopecia first described in 1994. Since then, its prevalence has been steadily increasing. Nowadays, it is one of the most common types of cicatricial alopecia. FFA is characterized by a frontal and/or temporoparietal hairline recession, leading to a cicatricial alopecic band. Eyebrow alopecia is commonly associated, and eyelash, limb, axillae and pubis alopecia can also be found. Facial papules are noted in some patients, especially over the temples. Some patients may have pruritus and/or trichodynia. The aetiology of FFA is still unknown, although hormonal and genetic factors are thought to play an important role. The main reasons for considering the involvement of hormones in the pathogenesis are that women, and mostly of menopausal age, are affected more frequently than men, and there is a favourable outcome using 5-alpha reductase inhibitors as a treatment. Familial cases have been reported, although they represent a minority; in fact, familial history of FFA has been reported in up to 8% of patients with FFA. Autoimmunity is also thought to be involved in the aetiopathogenesis of FFA, so different autoimmune conditions have been described together with FFA, especially hypothyroidism. On the other hand, some external substances have also been considered as possible triggers in FFA, especially the use of sunscreens, since a report found a higher use of sunscreens in patients with FFA compared to control subjects, although its real involvement in the development of FFA remains still unclear and controversial. The main trichoscopic signs in FFA are perifollicular erythema and follicular hyperkeratosis. The absence of follicular openings is a key sign for the diagnosis of scarring alopecia, including FFA. Lonely hair sign is also a common finding. The loss of vellus hair in the hairline implantation is considered an early sign of FFA. The use of other image apparatus to evaluate FFA, such as optical coherence tomography, confocal microscopy, and sonography has been scarce. Sonography is a non-invasive tool which may be helpful in evaluating different skin conditions, although its use in alopecia, especially in FFA, is really limited, and the sonographic signs of FFA are not well known. Quality of life (QoL) is known to be affected in patients with alopecia, including some scarring types. Women with alopecia can consider themselves to be less feminine, as hair is an important element in identity and self-image. Questionnaires which are used to assess QoL in alopecia are usually the same ones used with general skin diseases, such as the Dermatology Quality Life Index (DLQI). No specific questionnaire has been developed for the assessment of QoL impairment in FFA. Histopathologically, FFA is characterized by a lichenoid lymphocytic infiltrate, located mainly around the upper follicle, that is isthmus and infundibulum, including the bulge area – where stem cells are placed -, as well as concentric perifollicular lamellar fibrosis. The loss of sebaceous glands is considered an early finding in FFA. Moreover, the inflammatory infiltrate, and also sebaceous gland atrophy and perifollicular fibrosis, have also been observed in normal-appearing scalp in patients with FFA. Despite the increasing interest from the dermatologists to unravel the enigmas around FFA, many questions are still waiting to be answered. Is FFA associated with another skin condition? If FFA is considered to be a disease which occurs when predisposed people are exposed to an unknown trigger, is there any genetic profile which may be a marker of a higher risk of developing FFA? Do the familial cases of FFA share the clinical features of non-familial cases of FFA? And what about sunscreens? Could the higher use of sunscreens found in FFA patients be due to another reason? If FFA patients are habitual users of sunscreens, do they have less actinic damage? In relation to the use of sonography to assess FFA, are there sonographic differences in the varied areas of a scalp in a patient with FFA? And regarding QoL disorders in FFA, have patients with FFA an impairment in their QoL? Could a specific questionnaire for the assessment of the QoL in FFA be more precise than the pre-existing ones? Finally, the presence of inflammatory infiltrate and perifollicular fibrosis in normal-appearing scalp in FFA patients have been detected, but are there more histopathological alterations in normalappearing scalp areas in patients with FFA? Are there any differences with the histopathological features in the hairline implantation and the normal-appearing scalp?