Table 1.

Causes, Features, and Topical and Systemic Treatments of Scarring and Non-Scarring Alopecias

Scarring Alopecia
Type	Cause and Features	Treatments	Reference
Discoid lupus erythematosus	A chronic and common form of cutaneous lupus, in which the lesions typically occur on the scalp and other sun-exposed areas characterized by follicular plugging, atrophy, and hyperpigmentation.	Topical corticosteroids; intralesional corticosteroid; topical calcineurin inhibitors; antimalarial agents; oral retinoids; and methotrexate.	[13,14]
Lichen planopilaris	Alopecia is characterized by multifocal and small lesions caused by a chronic and uncommon lymphocytic inflammation that leads to the selective destruction of hair follicles. Little Piccardi Lasseur syndrome, characterized by keratotic papules on the trunk and extremities, non-scarring alopecia of the axillary and pubic region, and cicatricial alopecia of the scalp.	Potent topical and intralesional corticosteroids; oral corticosteroids; hydroxychloroquine; oral retinoids; oral tetracyclines; cyclosporine; mycophenolate mofetil; azathioprine with concurrent systemic corticosteroids.	[15]
Central centrifugal cicatricial alopecia	A permanent hair loss in the crown region of the scalp caused by inflammation and scarring. Predominantly occurs in African descent women over 30 years old.	Potent topical or intralesional corticosteroids; systemic antibiotics; hydroxychloroquine; mycophenolate mofetil.	[16,17]
Pseudopelade of Brocq	An idiopathic and slowly progressive form of cicatricial alopecia, which usually affects middle-aged Caucasian women. This condition is characterized by multiple small flash-toned alopecic areas with irregular borders without any signs of hyperkeratosis or inflammation.	Potent topical and intralesional corticosteroids; topical minoxidil; hydroxychloroquine; oral corticosteroids; isotretinoin; mycophenolate mofetil.	[18,19]
Folliculitis decalvans	Uncommon scalp disease possibly triggered by Staphylococcus aureus and alteration of the patient’s local immune response. Erythematous patch, follicular pustules or papules, and follicular hyperkeratosis involving the vertex and the scalp’s occipital area are the clinical sign of this condition.	Combined topical and oral antibiotics; topical or intralesional corticosteroids; isotretinoin; topical antimicrobial or antiseptic therapy.	[11,20]
Dissecting folliculitis	Rare alopecia characterized by a deep follicular occlusion, followed by follicular rupture and a deep inflammation of the hair follicle’s bulb.	Isotretinoin orally; topical or intralesional corticosteroids; oral or topical antibiotics; systemic corticosteroids; dapsone; and laser epilation.	[21,22]
Acne keloidalis	A chronic form of scarring folliculitis that affects mostly African descent men. The exact cause remains unknown. The inciting agents are multifactorial such as androgens, inflammation, infection, trauma, genetics, and growing hair. This condition is characterized by papules, pustules, and, sometimes, tumorous masses in the scalp’s nuchal or occipital regions.	Potent topical or intralesional corticosteroids; oral antibiotics; and surgical excision.	[23]
Non-Scarring Alopecia
Type	Cause and Features	Treatments	Reference
Alopecia areata	Specific autoimmune disease of the hair follicle with a genetic basis. Acute patchy hair loss is frequently reported.	Intralesional corticosteroids; topical corticosteroids; and minoxidil.	[10,24]
Tinea capitis	Alopecia caused by dermatophyte fungal infection on the scalp hair with predominance in children. Scaling with little hair loss to extensive alopecia, together with large inflammatory and pustular plaques.	Oral terbinafine, itraconazole, fluconazole, or griseofulvin. Topical antifungal as a complementary therapy to oral therapy.	[25]
Trichotillomania	Hair-pulling disorder producing hair loss and functional impairment.	Optimal treatment is unknown; selective serotonin reuptake inhibitors; behavioral therapy.	[26]
Telogen effluvium	Excessive shedding of hair, caused by an abnormality in the normal hair cycle, triggered by several factors such as drugs, physiological and emotional stress, and medical conditions.	Remove the underlying cause; topical corticosteroids.	[27]
Anagen effluvium	Chemotherapy-induced alopecia characterized by a diffuse hair loss days to weeks after exposure to a chemotherapeutic agent.	No pharmacologic intervention has been proven effective, although minoxidil may speed up the regrowth period.	[28]
Androgenic alopecia	The most common type of progressive hair loss with genetic causes. Men: typically involve frontal and vertex areas while preserving the occipital region. Women: diffuse hair thinning of the vertex with sparing of the frontal hairline.	Men: topical minoxidil (2% or 5% solution); oral finasteride. Women: topical minoxidil (1-5% solution).	[6,29]