Initial Evaluation of Acute Diffuse or Patchy Hair Loss
Acute hair loss over several weeks should be assessed first by determining whether alopecia is nonscarring or scarring based on scalp examination findings such as preservation or absence of follicular openings. Scarring alopecia should be referred to dermatology because it can be irreversible. [1]
A structured assessment should include characterization of the pattern (diffuse shedding versus patchy loss), tempo (abrupt versus gradual), scalp symptoms (pruritus, scale, pustules), and triggers (recent febrile illness, stress, pregnancy/postpartum, medication exposure, and systemic disease). [1]
Focused History Elements
History should evaluate physiologic or emotional stressors because telogen effluvium is a nonscarring, noninflammatory alopecia associated with relatively sudden onset and typically regrows after removal of the precipitating cause. [1]
History should evaluate recent chemotherapy or other mitotic insults because anagen effluvium can cause abnormal diffuse hair loss occurring days to weeks after exposure. [1]
History should evaluate recent pregnancy or postpartum state and systemic symptoms such as fatigue and weight change because endocrine disease such as hypothyroidism can contribute to diffuse hair loss. [1]
History should review topical and physical scalp exposures including hairstyles that increase traction and hair products that cause trauma or breakage because traction and hair-shaft disorders can mimic alopecia. [1]
History should evaluate psychiatric symptoms when patches of loss suggest trichotillomania because the best approach requires addressing the underlying behavioral disorder. [1]
Physical Examination and Triage
Physical examination should focus on the scalp surface and hair shafts to distinguish nonscarring versus scarring alopecia and to identify patterns of focal disease. [1]
Scalp inspection should assess for scaling, pustules, crusts, erosions, erythema, and local adenopathy because these findings suggest infectious causes such as tinea capitis. [1]
A hair pull test can be used to assess active shedding, with a positive pull test defined as more than 10% of hairs removed (approximately four to six hairs) supporting active hair shedding and suggesting telogen effluvium, anagen effluvium, or alopecia areata. [1]
Urgent or expedited dermatology referral is indicated when scarring is suspected or when infection is suspected with inflammatory lesions because prompt diagnosis and targeted therapy are needed. [1]
Diagnostic Differentials to Consider in the First Visit
Key nonscarring categories include diffuse shedding disorders and focal disorders. [1]
Diffuse causes to prioritize include telogen effluvium and anagen effluvium. Telogen effluvium typically presents as clumps of hair shed over a relatively sudden period after a precipitating event and is usually self-limited after removal of the cause. [1]
Anagen effluvium should be considered when diffuse hair loss occurs days to weeks after exposure to a mitotic toxin such as chemotherapy. [1]
Patchy causes to prioritize include alopecia areata, which presents as acute, patchy hair loss with characteristic exam findings and is often self-limited. [1]
Tinea capitis should be considered when patches of alopecia are associated with scaling, pustules, crusts, or lymphadenopathy and typically requires systemic antifungal therapy. [1]
Traction-related alopecia and hair-shaft breakage disorders such as trichorrhexis nodosa should be considered when scalp mechanics or hair processing suggest trauma rather than follicular destruction. [1]
Laboratory Testing and Imaging Indications
Routine laboratory testing is not indicated for all hair loss presentations. Laboratory testing should be performed when history or physical examination findings suggest an underlying comorbidity. [1]
When indicated by systemic features or suspected endocrine or hematologic contributors, laboratory evaluation commonly includes complete blood count and thyroid-stimulating hormone level. [1]
Inflammatory or infectious scalp findings should prompt appropriate microbiologic testing such as fungal cultures when tinea capitis is suspected. [1]
Management Based on Clinical Pattern
Telogen effluvium management
Telogen effluvium management should focus on removing the precipitating cause when identified and providing reassurance. This condition typically resolves within two to six months after the inciting factor is removed. [1]
Anagen effluvium management
No pharmacologic intervention has been proven effective for anagen effluvium. Management should emphasize supportive care and addressing the underlying exposure. [1]
Alopecia areata management
Alopecia areata can be treated with intralesional corticosteroids. This disorder can have a high rate of spontaneous remission. [1]
Diagnostic evaluation should follow an alopecia areata diagnostic framework that supports clinical diagnosis and selective use of further diagnostic steps when clinical findings are inconclusive or when other diagnoses such as scarring alopecia cannot be excluded. [2]
Tinea capitis management
Tinea capitis should be treated with systemic antifungal therapy because topical treatment alone does not penetrate hair follicles. [1]
Traction and hair-shaft trauma management
Management of traction alopecia should focus on decreasing tension on the hair and stopping the injurious hairstyle or hair-handling behavior. [1]
Management of trichorrhexis nodosa should focus on stopping the offending actions that cause hair shaft breakage. [1]
Trichotillomania management
Trichotillomania management should incorporate behavioral therapy approaches such as cognitive behavior therapy with habit reversal. Medical therapy may be more effective when combined with cognitive behavior therapy. [1]
Treatment Initiation Thresholds and Follow-Up
Treatment decisions should be driven by the clinical category established at the initial visit. [1]
Reversible nonscarring causes should receive targeted treatment or counseling based on the dominant category, with follow-up to confirm clinical trajectory and to reassess for emergent signs of scarring or infection. [1]
Common Pitfalls to Avoid
Assuming scarring alopecia is benign should be avoided because scarring alopecia may be irreversible and requires dermatology evaluation when follicular openings are absent or scarring is suspected. [1]
Overlooking infectious etiologies should be avoided because inflammatory scalp findings such as scaling, pustules, crusts, erosions, erythema, or local adenopathy can indicate tinea capitis and require systemic antifungal therapy rather than reassurance alone. [1]
Over-reliance on nonspecific shedding history should be avoided because hair loss workup should be guided by pattern recognition and exam findings, with laboratory testing reserved for cases with comorbidity suggestions. [1]
Goals of Therapy
The goal for telogen effluvium is resolution after removal of the precipitating cause plus reassurance about the typical self-limited course. [1]
The goal for alopecia areata is regrowth through targeted anti-inflammatory therapy such as intralesional corticosteroids for selected cases. [1]
The goal for tinea capitis is eradication of infection with systemic antifungal therapy to prevent persistence or progression. [1]
The goal for trauma- or traction-related alopecia is cessation of ongoing mechanical injury to allow regrowth and reduce further breakage or follicular damage. [1]
The goal for behavior-associated alopecia is improvement in hair-pulling behavior using behavioral therapy strategies to reduce ongoing hair shaft trauma. [1]