Clinical and trichoscopic characteristics of temporal triangular alopecia: A multicenter study

Abstract

To the Editor: Congenital triangular alopecia, also called temporal triangular alopecia (TTA), is an asymptomatic permanent circumscribed noncicatricial alopecia.1Tosti A. Congenital triangular alopecia. Report of fourteen cases.J Am Acad Dermatol. 1987; 16: 991-993Abstract Full Text PDF PubMed Scopus (44) Google Scholar2Ruggirei M. Temporal triangular alopecia in association with mental retardation and epilepsy in a mother and daughter.Arch Dermatol. 2000; 136: 426-427Crossref PubMed Scopus (54) Google Scholar It manifests as an alopecic patch without any underlying cutaneous alterations usually confined to one frontotemporal region of the scalp. Fine vellus hairs may be present. TTA is usually noted in children between 3 and 6 years of age and has been associated with Down syndrome, leukonychia, sectorial hyperpigmentation of the iris, woolly hair, mental retardation, epilepsy, and other malformations, such as Dandy-Walker and LEOPARD syndromes. The genetic basis of TTA is unknown but a paradominant trait is suspected.3Happle R. Congenital triangular alopecia may be categorized as a paradominant trait.Eur J Dermatol. 2003; 13: 346-347PubMed Google Scholar The major differential diagnoses are the non-cicatricial circumscribed alopecias including alopecia areata, trichotillomania, traction alopecia, and aplasia cutis congenita.4Inui S. Trichoscopy for common hair loss diseases: algorithmic method for diagnosis.J Dermatol. 2011; 38: 71-75Crossref PubMed Scopus (81) Google Scholar To our knowledge neither large series of patients with TTA nor the dermoscopic features of the condition have been published.5Iorizzo M. Pazzaglia M. Starace M. Militello G. Tosti A. Videodermoscopy: a useful tool for diagnosing congenital triangular alopecia.Pediatr Dermatol. 2008; 25: 652-654Crossref PubMed Scopus (28) Google Scholar, 6Karadağ Köse O. Güleç A.T. Temporal triangular alopecia: significance of trichoscopy in differential diagnosis.J Eur Acad Dermatol Venereol. 2015; 29: 1621-1625Crossref PubMed Scopus (21) Google Scholar The objective of this observational multicenter study was to describe the clinical and trichoscopic findings of patients with TTA. Thirty-one patients with TTA were seen in 2014 at 6 hospitals in Spain: Jaen, Seville, Madrid, Barcelona, Valencia, and Granada. Variables were (1) demographics: age, sex, height, weight, body mass index; (2) clinical characteristics: age at diagnosis, shape (triangular, oval, lancet; unilateral/bilateral), and size (maximum diameter); (3) dermatologic and nondermatologic comorbidities; (4) trichoscopic features with nonpolarizing or polarizing dermoscope; (5) treatment regimen: expectant, topical corticosteroids, local injection of corticosteroids, topical minoxidil, surgery; (6) efficacy of treatment: patient's perception and dermatologist's perception. Statistical analysis was performed using SPSS 15.0 software. Seventeen females and 14 males were included. The major clinical features are listed in Table I. More than half of patients (n=19) were diagnosed at birth. Triangular shape was the most prevalent and was seen in 15 cases (48.4%), followed by oval shape in 12 cases (38.7%) and lancet shape in 4 cases (12.9%). Twenty-one of 28 cases were on the left side and 7 cases were on the right (Fig 1). The rate of bilateral occurrence was 6.5% (2 cases). Of 26 lesions measured, mean maximum diameter was 3.67 cm. Mean size of lesions was 3.6 cm in 20 patients younger than 16 years old and 3.9 cm in patients older than 16 years. Only 5 cases (16.1%) presented with nondermatologic comorbidities, including prematurity at birth, Down syndrome, and bronchial asthma. One adult patient was referred for deep venous thrombosis and 1 case presented with Gilbert's syndrome. A history of dermatologic comorbidities, including atopic dermatitis (14/17), psoriasis, contact dermatitis, amyloidosis, SAHA syndrome (seborrhea, acne, hirsutism, and alopecia), and vitiligo, was present in 54.8% (17/31) of subjects.Table IClinical characteristics of patients with temporal triangular alopeciaClinical characteristicsTotalMale (N=14) (45.2%)Female (N=17) (54.8%)Age of diagnosisN=31TotalX=1.9 yrS=4.2Range=0-18X=0.9 yrS=1.5X=2.8 yrS=5.5ShapeN=31Triangular15 (48.4%)7 (50%)8 (47%)Oval12 (38.7%)5 (35.7%)7 (41.2%)Lancet4 (12.9%)2 (14.3%)2 (11.8%)Maximum diameterN=26<16 yrN=20X=3.6 cm (S=1.2)>16 yrN=6X= 3.9 cm (S=0.6)TotalX=3.67 cm (S=1.15)Unilateral/bilateralN=30Unilateral28 (93.3%)13 (92.9%)15 (88.2%)Bilateral2 (6.7%)1 (7.1%)1 (5.9%)SideN=28Left21 (75%)8 (57.1%)13 (76.5%)Right7 (25%)4 (28.6)3 (17.6%)X, Mean; S, standard deviation; N, number of patients. Open table in a new tab X, Mean; S, standard deviation; N, number of patients. Trichoscopy was performed in 19 cases (61.3%), mostly using a contact dermoscope (16 cases) (Fig 2). Trichoscopic features are listed in Table II. White hairs and diversity of diameter were the most frequently features observed (18/19), followed by vellus hair (16/19), empty follicles (12/19), and white dots (10/19). Diagnosis was made by clinical appearance, and biopsy was not necessary. No family history of TTA was obtained. No improvement with expectant treatment was apparent after a mean of 81.96 months. Five patients (16.1%) used topical corticosteroids and three patients were treated with intralesional corticosteroids (triamcinolone acetonide) with no evidence of improvement. One patient experienced improvement with topical minoxidil 5% and topical corticosteroids after 6 months of treatment. No patients underwent surgery.Table IITrichoscopic features observed in temporal triangular alopeciaTrichoscopic sign (N:19)Frequency<16 years (N=13)≥16 years (N= 6)White hairs18 (94.7%)12 (92.3%)6 (100%)Diversity of diameter18 (94.8%)12 (92.3%)6 (100%)Vellus hair surrounded by terminal hair16 (84.2%)12 (92.3%)4 (66.6%)Empty follicles12 (63.1%)6 (46.1%)6 (100%)White dots10 (52.6%)7 (53.8%)3 (50%)Arboriform vascular pattern4 (21%)04 (100%)Yellow dots3 (15.8%)03 (100%)Epidermal scale3 (15.8%)2 (15.4%)1 (16.6%)Broken hairs2 (10.5%)1 (7.7%)1 (16.6%)Cadaveric hairs1 (5.2%)01 (16.6%)Black dots1 (5.2%)01 (16.6%)Exclamation point hairs000 Open table in a new tab Based on our study, TTA affects both sexes with a slight predominance in females. The left side is most often affected but it can be bilateral. Most cases are sporadic and have a triangular shape averaging 3.6 cm in length; other malformations are generally not found. It is usually diagnosed during the first 2 years of life. Trichoscopy is a useful tool for the diagnosis of uncertain cases and may reveal white hairs, vellus hairs, and hairs of diverse diameters. There is no consistently effective treatment.