Alopecia: a pathologist's view

Agent specific effects of anticoagulant induced alopecia

Alopecia has been observed with many anticoagulants although the mechanism is unclear. A 20 year old female with recurrent DVTs developed alopecia with multiple anticoagulants, including heparin derivatives and the new oral anticoagulants. This resolved with discontinuation of the agents. The patient was ultimately able to be anticoagulated with fondaparinux long term without any alopecia. This case addresses the Key Clinical Question of management and recognition of anticoagulant induced alopecia. This side effect can result from almost any of the available agents and is quickly reversible, underlining the importance of tailoring treatment to the individual and their experiences.

Traditional Anticoagulants and Hair Loss: A Role for Direct Oral Anticoagulants? A Review of the Literature

Hair loss is associated with the anticoagulants heparin and warfarin. With the recent availability of direct oral anticoagulants (DOACs) it is of clinical interest to know if they are implicated with hair loss and/or whether they could be successfully prescribed for patients who suffer from coumarin- or heparin-related alopecia. Initially reports of heparin- and coumarin-associated alopecia available through PubMed and Medline were explored in order to establish the cause of this side effect. Currently there is a lack of unanimity on why anticoagulants cause alopecia. However, timing and presentation strongly suggest that telogen effluvium is part of the process. The observation that both heparins and coumarins cause a similar pattern of hair loss suggests a shared mechanism related to anticoagulant activity. To date, the World Health Organization has received 405 reports of DOAC-associated alopecia through their pharmacovigilance database VigiBase^®. Additionally, real world registry data describes an alopecia incidence of 4.4 per 100 patient years in patients prescribed rivaroxaban and dabigatran. Further widespread clinical experience is required to ascertain if this is true, but early indications suggest that DOACs are implicated in hair loss and will not provide a suitable alternative for patients suffering from alopecia related to traditional anticoagulants.

Histologic features of alopecias-part I: nonscarring alopecias

The diagnosis of disorders of the hair and scalp can generally be made on clinical grounds, but clinical signs are not always diagnostic and in some cases more invasive techniques, such as a biopsy, may be necessary. This 2-part article is a detailed review of the histologic features of the main types of alopecia based on the traditional classification of these disorders into 2 major groups: scarring and nonscarring alopecias. Scarring alopecias are disorders in which the hair follicle is replaced by fibrous scar tissue, a process that leads to permanent hair loss. In nonscarring alopecias, the follicles are preserved and hair growth can resume when the cause of the problem is eliminated. In the first part of this review, we describe the histologic features of the main forms of nonscarring alopecia. Since a close clinical-pathological correlation is essential for making a correct histologic diagnosis of alopecia, we also include a brief description of the clinical features of the principal forms of this disorder.

Histopathologic Evaluation of Alopecias

The alopecias can be broadly classified into non-scarring and scarring forms. The latter are divided into primary and secondary scarring types. In primary scarring alopecias, the hair follicle is the prime target of destruction as opposed to secondary scarring alopecias in which it is involved in a neighboring non-follicular process that impinges upon the follicle and ultimately destroys it. After an initial overview and a critique on the concept of scarring versus non-scarring, we outline in detail the histopathologic presentation of the major forms of alopecias. Because the correct histopathologic diagnosis often requires close clinicopathologic correlation, a brief description of the clinical presentation is included. This review also discusses important pathogenetic concepts, such as stem cell failure.

A clinicopathologic study of scarring alopecia due to lichen planus: comparison with scarring alopecia in discoid lupus erythematosus and pseudopelade

The clinicohistologic findings in 68 patients with lichen planus scarring alopecia (LP) were compared with those of 25 patients with discoid lupus erythematosus of the scalp (DLE) and 25 with pseudopelade (PP). The combination of diffuse scaling, erythema, telangiectases, and mottled hyperpigmentation within areas of scarring alopecia was a distinctive feature of DLE, whereas the clinical picture of PP was indistinguishable from that seen in 29 patients with LP. In most patients with LP, the histologic changes involved only the follicles and the perifollicular dermis. Less frequently, the inflammatory process extended to the epidermis and the papillary dermis. In all cases, histopathologic features allowed LP to be distinguished from DLE regardless of the stage of the disease. The finding of a bandlike fibrotic thickening of the papillary dermis accompanied by fibrotic tracts at sites of destroyed follicles appeared to be a hallmark of "burnt out" lesions of LP. This histologic clue may be helpful in achieving a specific diagnosis of LP in cases that fulfill the clinical criteria for PP.

Postoperative pressure-induced alopecia: report of a case and discussion of the role of apoptosis in non-scarring alopecia

We report a case of postoperative pressure induced alopecia in a 21-year-old black female after multiple intraoperative procedures. The histopathology is distinctive and demonstrated features in common with trichotillomania and alopecia areata, including the presence of pigment casts, catagen follicles, melanophages and apoptotic bodies. External hair manipulation is considered the primary event in the etiology of pigment casts, however, our present case demonstrated numerous pigment casts despite a complete lack of evidence of external hair manipulation. We performed pattern analysis and in situ end-labeling in 19 cases of non-scarring alopecia. Pigment casts were seen in postoperative alopecia (1 case), alopecia areata (1 case) and trichotillomania (5 cases). These forms of alopecia have in common the sudden termination of the anagen phase of the hair cycle. When the anagen portion of the hair cycle is prematurely disrupted hairs enter into catagen. Pigment casts may represent a non-specific reaction pattern of follicles that are suddenly transformed from anagen to catagen. We therefore propose that hair manipulation is not uniquely responsible for the formation of pigment casts. The primary pathophysiology resulting in the formation of pigment casts more correctly reflects the sudden termination of the anagen phase of the hair cycle.

Estrogen and progesterone receptors in androgenic alopecia versus alopecia areata

In some situations, hair growth is under hormonal control. Androgenic alopecia is characterized as hormonally driven hair loss in the genetically susceptible individual. During pregnancy, hair growth is increased, as estrogen appears to prolong the anagen phase. However, postpartum hair loss is common, and thus may be related to a decrease in estrogen and or progesterone levels. In contrast, alopecia areata is not considered to be under hormonal control. We compared the immunohistochemical staining characteristics of nine cases of androgenic alopecia with those of 13 cases of alopecia areata using estrogen receptor (ER) and progesterone receptor (PR) markers. Estrogen receptor positivity in the dermal papilla was found in only two of 13 cases of alopecia areata, and in one case of androgenic alopecia. Six of 13 cases of alopecia areata demonstrated focal reactivity with the progesterone marker in a similar location, while only three cases of androgenic alopecia showed positivity with this antibody. Examination of the perifollicular fibroblasts for the ER marker showed positivity in one of 13 cases of alopecia areata and in one case of androgenic alopecia. Two cases of alopecia areata revealed focal staining in this location for the PR marker, while the androgenic alopecia cases failed to stain. These results indicate that estrogen and progesterone receptor expression is not significantly increased or decreased in the pilosebaceous units or surrounding mesenchymal cells in androgenic alopecia vs. alopecia areata. Therefore, an indirectly mediated process of estrogen/progesterone control on hair growth and development must be presumed for cases of androgenic alopecia.

Vertical and transverse sections of alopecia biopsy specimens: combining the two to maximize diagnostic yield

BACKGROUND

Traditional vertical sections of scalp biopsy specimens contain few hair follicles. For this reason transverse sections of scalp biopsy specimens have been advocated. Both methods have advantages and disadvantages. We have developed a simple method that we believe offers the best of both methods.

OBJECTIVE

Our purpose was to assess the impact of combining vertical and transverse sections of scalp biopsy specimens.

METHODS

Two 4 mm punch biopsies are performed. One specimen is bisected vertically: half for hematoxylin-eosin (H-E) staining, half for direct immunofluorescence. The second specimen is bisected transversely and submitted for H-E. The three pieces of tissue for H-E staining are embedded in a single cassette.

RESULTS

Because a biopsy specimen for direct immunofluorescence is commonly obtained in cases of alopecia, our method does not add a surgical procedure. All three pieces of tissue for H-E staining are embedded in a single paraffin block. Therefore the cost of histologic interpretation is not increased. Our diagnostic yield improved. Transverse sections were superior in cases of lupus erythematosus and lichen planopilaris with focal follicular involvement. Features of the follicular degeneration syndrome were also best demonstrated in transverse sections. Interface changes, lupus panniculitis, miniaturized hairs, and trichomalacia were better demonstrated in vertical sections.

CONCLUSION

Our method exploits the advantages of both vertical and transverse sections and improves diagnostic yield without increasing cost.