Scarring alopecia

Scarring alopecia refers to a group of disorders of various etiologies that cause permanent hair loss. In this article, we focus on primary cicatricial alopecia, a group of diseases in which the hair follicle is the main target of the inflammatory process. These disorders are currently classified as lymphocytic, neutrophilic, or mixed according to the cells that make up the inflammatory infiltrate. The pathogenesis of the majority of these conditions is not fully understood and they may have similar clinical features, often making it necessary to perform 1 or more skin biopsies in order to reach a diagnosis. Management depends on early and accurate diagnosis and aggressive treatment in some cases in order to prevent follicular destruction and scarring.     

Scarring alopecia

The scarring alopecias are a diverse group of diseases characterized by the combination of follicular destruction and dermal scarring. In this article we divide scarring alopecias into three broad categories, pediatric diseases, perifollicular lymphocytic diseases, and folliculopustular diseases, and discuss selected entities from each category.     

Scarring alopecia associated with mastocytosis

BACKGROUND: Mastocytosis is comprised of a group of heterogeneous diseases involving various organs. Urticaria pigmentosa is the most common manifestation of cutaneous mastocytosis; others include mastocytoma, diffuse mastocytosis, and telangiectasia macularis eruptiva perstans. METHODS: We describe a case of indolent mastocytosis presenting as scarring alopecia. The scalp biopsy revealed a perifollicular and dermal inflammatory infiltrate composed predominantly of mast cells, which was confirmed by tryptase and Giemsa stains. RESULTS: The preponderance of mast cells in the biopsy prompted testing for urine N-methylhistamine levels, which were elevated and confirmed the diagnosis of mastocytosis. This is the first report of mastocytosis presenting as scarring alopecia. CONCLUSIONS: This case suggests that the diagnosis of mastocytosis should be entertained in patients presenting with scarring alopecia accompanied by an intense mast cell infiltrate on scalp biopsy and also supports the notion that mast cells may be involved in the pathogenesis of alopecia.     

Scarring alopecia in discoid lupus erythematosus

The clinicopathological features of the scarring alopecia of discoid lupus erythematosus (DLE) were studied. Scarring alopecia was present in 34% of 89 patients with DLE and was associated with a prolonged disease course. More than half these patients had scalp involvement at the onset of the disease. There was a significant reduction in size of sebaceous glands in affected scalp. Perifollicular lymphocytic inflammation was maximal around the mid-follicle at the level of the sebaceous gland, which seems to be an important functional level in the follicle. There are changes in the expression of the matrix molecules, the proteoglycans, in the connective tissue sheath and the keratin intermediate filaments in the outer root sheath cells at this level in normal scalp and in diseased scalp. Loss of a population of mid-follicular stem cells may be important in the pathogenesis of scarring alopecia in DLE.     

Scarring alopecia: clinical and pathologic study of 54 African-American women

Background  Cicatricial or scarring alopecia results in the destruction of hair follicles and is a significant cosmetic concern in African-American women.
Objective  To correlate the clinical examination and histologic findings in African-American women with scarring alopecia with a history of hairstyling practices.
Methods  We reviewed retrospectively the medical records and scalp biopsy specimens of 54 women with scarring alopecia. Patients were selected from two dermatologic practices in the Detroit Metropolitan area.
Results  Alopecia commonly presents in patients who use a variety of traumatic haircare techniques, including chemical and physical straighteners, traction, braiding, hair extensions, hair gluing, and chemical curls. Histologic findings are centered around the follicular infundibulum with a lymphocytic infiltrate and perifollicular fibrosis.
Conclusion  Traumatic hairstyling techniques are common in African-American women, and all result in a similar picture of a peri-infundibular lymphocytic infiltrate and fibrosis, leading to alopecia.     

Scarring alopecia in chronic cutaneous lupus erythematosus with neutrophils: A new scenario with therapeutic connotations

The relationship between autoinflammatory and autoimmune conditions has been demonstrated in recent decades. Several autoimmune conditions exhibit an autoinflammatory component, which can manifest in various ways. Neutrophilic dermatosis in the context of lupus erythematosus (LE) is one example. Otherwise, neutrophils are rare in LE, except for the bullous variant and nonbullous neutrophilic LE. In this paper, we describe a case of scarring alopecia due to LE that stopped responding to a treatment that had been effective for years. The biopsy specimen demonstrated the presence of neutrophils in the inflammatory infiltrate. A treatment with dapsone was prescribed and yielded rapid improvement. This first case of scarring alopecia in the context of nonbullous neutrophilic LE emphasizes the importance of the infiltrate in determining the optimal therapeutic choice.     

Muir-Torre syndrome: role of the dermatopathologist in diagnosis

Muir-Torre syndrome (MTS) is an autosomal dominantly inherited disorder characterized by sebaceous lesions and visceral malignancies. The defect is thought to be the result of a mutation in mismatch repair genes and associated with microsatellite instability. Two cases whose diagnoses were suggested first by the dermatopathologist are discussed. The first is a 47-year-old white man who over the past 6 years developed multiple sebaceous lesions. Due to the number of sebaceous lesions and their morphology, the possible diagnosis of MTS was suggested by the dermatopathologist. Subsequently, a lesion in the right colon was found during colonoscopy that proved to be a poorly differentiated cecal adenocarcinoma. A pedigree analysis revealed other family members afflicted with multiple malignancies. Genetic testing of the colonic adenocarcinoma showed microsatellite instability. The second patient is a 50-year-old white man who underwent biopsy of a skin lesion that showed features of both a sebaceous hyperplasia and sebaceous adenoma. Because of the mixed, unusual features of the lesion, the dermatopathologist suggested the diagnosis of MTS. It was later confirmed that the patient had a history of malignancies of the colon and kidney as well as a family history significant for multiple malignant neoplasms. These cases demonstrate the important role of the dermatopathologist in alerting the clinician to the possibility of Muir-Torre syndrome when the diagnosis of a sebaceous neoplasm is made, especially when unusual histologic features are observed.     

Newly recognized neural neoplasms relevant to the dermatopathologist.

Several forms of neural neoplasia have recently been described and are still not well known. Entities such as nerve sheath myxoma, cellular schwannoma, plexiform schwannoma, and palisaded encapsulated neuroma have special clinicopathologic relevance and should be diagnosed correctly by the dermatopathologist. Familiarity with these new entities and with their differential diagnosis contributes to better patient management.