Table 1. Clinical differential diagnosis of moth-eaten alopecia syphilitica

Condition	Clinical Presentation	Pathology	Lab	Treatment
Alopecia areata	Exclamation mark hairs Sudden loss, well-demarcated	A “swarm of bees” appearance of T lymphocyte infiltrates in the peribulbar region	CBC ², TFT, Thyroid antibodies	Corticosteriods (intralesional, systemic, or topical)
Alopecia neoplastica	Presents months to years after diagnosis of primary malignancy	Infiltration of tumor cells from primary malignancy	Biopsy	Treatment of primary malignancy
Alopecia syphilitica	Moth-eaten or diffuse pattern, or combination of both Other symptoms or lesions of secondary syphilis	No dermoepidermal changes Sparse lymphocytic infiltrate Absence or rare peribulbal eosinophils Absence of small or abnormal anagen hair follicles Plasma cells may be present	Serology	Benzathine penicillin G 2.4 million units, 1-3 weekly intramuscular injection(s)
Tinea capitis	Erythematous patch with scaling Brittle and broken hair “Black dot” appearance Kerion, if superinfected Cervical lymphadenopathy	Endothrix-hair shaft filled with hyphae and spores Ectothrix-hyphae and spores outside of hair	Culture KOH stain of scalp scrapings Wood’s light	Systemic antifungals for 6-8 weeks
Trichotillomania	Irregular, localized patches Broken hairs of varying lengths Patient admits to pulling on hairs	Empty follicles with remnant hair bulb with exudates or hemorrhage Complete distortion of a fully developed termina hair in the bulb No inflammation of hair bulb or atrophic anagen hairs	Biopsy	Parental support/education, Parental support/education, pharmacotherapy, depending on age and severity; may need psychiatric consultation

1. CBC, complete blood count and platelets; KOH, potassium hydroxide; TFT, thyroid function test

2. If a macrocytic anemia is present, vitamin B12 level and patietal cell antibodies might be considered.