Table 1.

Epidemiology, symptoms, clinical manifestations, dermoscopic findings, and histological features of the most common scarring alopecias associated with itch

	History	Symptoms and itching	Clinical features	Dermoscopy	Histological features
Lichen planopilaris (LPP)	Women > men Peak age between 30 and 60 years of age [79] Non-scalp lichen planus in 17–28% of patients with LPP [81]	Shedding/hair loss (100%), scale (80%), and scalp tenderness (72%) [82] Pruritus variable (54.34–90%) [79, 83, 84]	Whitish atrophic or scarring patches on the scalp with complete loss of follicular orifices [80] (Fig. 7)	Absence of follicular openings, peripilar casts, broken hairs Vellus hairs are usually absent [12] (Fig. 8)	Lichenoid dermatitis at the dermoepidermal junction surrounding the follicular infundibulum and the isthmus A perivascular infiltrate may be minimal, superficial and usually perifollicular Epidermal and dermal mucin is usually absent [85]
Frontal fibrosing alopecia	Primarily affects postmenopausal women [86]	Pruritus variable 35–67%[87, 88, 89, 90] Burning and pain sensation 21% [89] Pain 17%, burning 8% [90]	Progressive frontotemporal hairline recession, perifollicular erythema, glabellar red dots perifollicular papules, eyebrow loss, eyelashes and body hair loss [87, 91] “Lonely hair” sign [92]	Absence of vellus hair, peripilar casts, broken hairs, “V sign” and black dots [12]	Same as LPP [82]
Discoid lupus	Women > men Young to middle age women (between 20 and 40 years) [81, 82]	Increased shedding (100%), pruritus (65%), and scalp tenderness (26.2%) [83]	Erythematous patches of alopecia, follicular hyperkeratosis, hyperpigmentation or loss of pigment and telangiectasias [81, 82]	Loss of follicular openings, white patches, peripilar casts, keratotic plugs, red dots, enlarged branching vessels [12]	Vacuolar interface alteration of the follicular epithelium with scattered dyskeratotic keratinocytes, cytoid bodies, and a variable dense periadnexal and interstitial lymphocytic infiltrate with dermal mucin Superficial and deep perivasculitis Sebaceous glands are atrophied or absent [82]
Central centrifugal cicatricial alopecia (CCCA)	Most common cause of permanent hair loss in African-Americans Middle-aged black females [85] May be inherited in an autosomal dominant pattern [93]	Symptoms may be trivial or absent: mild pruritus, pain, or tenderness may occur in involved areas [85] Positive correlation between CCCA severity score and peak itch ratings [94]	Flesh-colored, noninflammatory cicatricial alopecia of the central scalp that enlarges centrifugally [82, 85]	Irregularly distributed pinpoint white dots and irregular white patches and peripilar white-gray halo surrounding the hairs within the patches [12]	Premature inner root sheath desquamation is a characteristic but nonspecific finding Active disease: perifollicular lymphocytic infiltrate surrounds the upper follicle; concentric lamellar fibroplasia occurs around mid- and upper follicles Advanced disease: perifollicular granulomatous inflammation and presence of hair shaft foreign-body giant cells End-stage disease: follicular fibrosis with retention of erector pili [82]
Folliculitis decalvans	Young adults of both genders Slight male predominance [95]	Pruritus 68%, trichodynia 30% [95]	Scarring alopecic patches with follicular pustules, crusts and tufted hairs [95] Irregularly shaped, atrophic flesh-colored or ivory-white patches of cicatricial alopecia develop [82, 96] Predominantly involves the vertex and occipital area of the scalp [96]	Polytrichia, perifollicular erythema in a starburst pattern, yellowish tubular scaling, crusting and follicular pustules Chronic lesions: ivory-white and milky-red areas without follicular orifices [12]	Neutrophilic primary cicatricial alopecia [97] Active disease: acneiform infundibular dilatation; variably dense, intrafollicular and perifollicular neutrophilic infiltrate affects the upper and middle parts of the follicle Progression: the infiltrate composed of neutrophils, lymphocytes, and plasma cells extends into the adventitial dermis; granulomatous inflammation occurs Late-stage disease: follicular and adventitial dermal fibrosis [82]