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The Exchange Frontal Fibrosing Alopecia: Making the Diagnosis

Frontal Fibrosing Alopecia: Making the Diagnosis

Frontal Fibrosing Alopecia: Making the Diagnosis Posted By:
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For many providers, seeing "hair loss" as the chief complaint on a patient's chart can induce dread. Imagine how the patient feels if their clinician lacks the knowledge and confidence to properly evaluate, diagnose, and educate them on their specific type of hair loss. One of the critical components of successfully treating patients with hair loss is being facile and confident in making an accurate diagnosis and providing the patient with clear education on their condition and disease trajectory. This brief article will focus on the diagnosis of frontal fibrosing alopecia (FFA) and how it differs clinically and histologically from the most common type of hair loss in women, androgenetic alopecia (AGA; also known as androgenic alopecia or female-pattern hair loss).

Differentiating FFA from AGA in women is important, as it has major implications for prognosis and treatment. AGA is a non-inflammatory, non-scarring alopecia that is characterized by progressive thinning over the vertex of the scalp and reduced ponytail diameter, which is caused as a result of progressive follicular miniaturization. It is quite common, affecting approximately 50% of women by the age of 50. On the other hand, FFA is a rare, inflammatory, scarring alopecia that results in follicular destruction, occurring almost exclusively in postmenopausal women, with rare cases reported in young women and even fewer in men.

Clinical presentation of these two types of hair loss is also quite different. The clinical history can provide insight into the diagnosis: AGA progresses slowly over several years or decades, whereas FFA often has an acute phase in which there is a rather rapid frontal hairline recession, which in some can be quite profound. FFA attacks the frontal and temporal hairlines—and many times, eyebrows—whereas in AGA, there is maintenance of the anterior hairline but widening of the midline part with generalized thinning. Less commonly, FFA involves the posterior auricular and occipital hairline, as well as hair of the pubic, axillary, and limb regions. Additionally, FFA can include the "lonely hair" sign, which is characterized by a single, preserved hair within a scarred plaque, representing a single hair that was somehow spared from inflammation. With FFA, inflammation can be visible on examination—characterized by perifollicular erythema, scale, papules, and even pustules. Given that the goal is to prevent further hair loss, early identification and treatment initiation is paramount.

Although biopsy is not always indicated, histologically FFA shows a perifollicular lichenoid lymphocytic infiltrate, reduced number of hair follicles, fibrosis, and scarring. If biopsy is indicated, one should opt for a 4-mm punch biopsy in an area with visible inflammation that is immediately adjacent to a scarred plaque. AGA is often a clinical diagnosis and does not require biopsy; however, if done, the sample should be sent for horizontal sectioning that will show preserved follicle count and miniaturized hair follicles with an abnormal terminal to vellus ratio.

In conclusion, understanding the basic key differences in clinical history, presentation, and histopathology will provide the clinician with a better understanding and therefore a greater ability to detect, differentiate, treat, and educate their patients on these two very different types of hair loss.

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