Differentials
Trichotillomania
SIGNS / SYMPTOMS
Patients with trichotillomania (compulsive hair pulling) may have other signs or symptoms of psychiatric/obsessive compulsive disorder. Nail-biting behavior may be associated.[19]
Odd or geometric patterns of hair loss or a Friar Tuck pattern of hair loss with broken or blunt-tip hairs are seen.
INVESTIGATIONS
Scalp biopsy shows melanin casts and trichomalacia.[20]
Tinea capitis
SIGNS / SYMPTOMS
Tinea capitis occurs most commonly in children.
The scalp is typically itchy, inflamed, and scaly; less commonly, there is kerion formation with boggy areas of scalp.
Lymph nodes are enlarged and tender.
INVESTIGATIONS
Scalp biopsy shows hyphae on fungal stain.
Fungal culture is positive.
Telogen effluvium
SIGNS / SYMPTOMS
Alopecia is diffuse.
There may be a history of a causative stressor (high fever, surgery, delivery) often at least 3 months before the onset of hair shedding.
INVESTIGATIONS
Biopsy shows increased number of telogen follicles.
Syphilitic alopecia
SIGNS / SYMPTOMS
There is a moth-eaten appearance of hair loss.
INVESTIGATIONS
Rapid plasma reagin (RPR) and fluorescent treponemal antibody absorption test (FTA-ABS) are positive.
SLE
SIGNS / SYMPTOMS
Alopecia is diffuse.
INVESTIGATIONS
ANA is positive.
Scarring alopecias
SIGNS / SYMPTOMS
Lack of follicular ostia with various degrees of associated inflammation, scale, and erythema depending on the subtype of scarring alopecia.
INVESTIGATIONS
Biopsy findings either show a lymphocyte-predominant, neutrophilic-predominant, or mixed inflammatory infiltrate (depending on the subtype of scarring alopecia) associated with destruction of hair follicles replaced by scarring.
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