Clinical history is usually that of a young female child with light hair that sheds easily. A classic contextual clue is a history of hair that does not require frequent cutting. The hair is often described to have unusual textures such as "sticky, matted, frizzy, and unmanageable." Often, parents report diffuse hair loss, and despite this, areas of complete hair loss usually are not present. Most commonly thinning is seen over the entire scalp or, as classically associated, the occipital scalp. Involvement of the eyebrows is uncommon but may be seen.[1]

A pull test is the cornerstone of diagnosis in loose anagen hair syndrome. It is performed by using gentle traction on approximately 40 to 60 scalp hairs. Telogen hairs normally represent 10% of scalp hairs, and thus, removal of 4 to 6 hairs is a normal finding in the hair pull test. Loose anagen hair syndrome, similar to telogen effluvium, will result in greater amounts of hair removed. Despite easy removal from the scalp, individual hairs in loose anagen hair syndrome have normal tensile strength and are not brittle. Hairs can be examined under light microscopy by dry-mounting the hair on a glass slide with a cover slip placed over top. In loose anagen hair syndrome anagen, hairs lack inner root sheaths and external root sheaths with a ruffled cuticle.[5] As loose hairs may be seen in unaffected individuals some propose a positive hair test contain 50% or more of anagen hairs.[1]

Diagnosis is usually based upon clinical history, physical exam, and light microscopy. Further stratification into clinical subtypes of loose anagen hair syndrome includes (1) sparse short hair, (2) diffuse or patchy unruly hair, and (3) adults with the excessive shedding of anagen hairs.[7] The utility of this is uncertain as it does not relate to changes in treatment and effect on prognosis is also uncertain. Additional laboratory testing is not routinely necessary.[8] Although usually a solitary self-resolving condition, if other comorbidities occur investigation of underlying syndromic diseases may be needed. Sporadic cases of loose anagen hair syndrome coexisting with Noonan syndrome, neurofibromatosis type 1, atopic dermatitis, trichorhinophalangeal syndrome, nail-patella syndrome, and FG syndrome have been described.[2]

Treatment is often unnecessary as the disease is often self-limited and improves with age. If treatment is pursued, topical minoxidil has been used as first-line therapy for those with significant disease burden.[1] The mechanism by which minoxidil is thought to be beneficial is by prolongation of the anagen phase.[3] Biotin therapy has been shown to be of no benefit,[7] and otherwise, only gentle hair care to avoid removal of loosely anchored hairs is recommended.[5]

Non-Scarring Alopecias of Childhood

• Short anagen syndrome (SAS): Caused by a shortened anagen phase.Similar clinical history (i.e., hair does not grow long and does not require cutting, short hair, diffuse alopecia)
  • Distinguished by SAS having a predominance of telogen hairs with trichoscopy and a lack of distinguishing features)
  • Similar treatment to loose anagen syndrome  [9]
• Telogen effluvium: Also presents as diffuse thinning but is uncommon in childhood. Clinical history may reveal physical or psychological trauma 3 to 4 months preceding onset. Telogen hairs will be seen with light microscopy.
• Aopecia areata: Often focal or diffuse areas of complete hair loss as opposed to the diffuse areas of thinning hair as seen in loose anagen hair syndrome.
• Androgenetic alopecia: Gradual thinning; miniaturization of follicles seen with a frontal or temporal distribution of hair loss. Telogen hair is seen with light microscopy.
• Trichotillomania: Unusual shape and size of hair loss. Often patchy with hairs at different stages of growth. Telogen hairs with fractures on light microscopy.[1]

Hair Shaft Disorders without Increased Fragility

• Uncombable hair syndrome: Clinically hair cannot be combed flat. The entire hair shaft is rigid with a triangular shape. Hair loss is not a predominant feature.
• Pili Annulati: characteristic alternating light and dark bands in the hair shafts that can be seen on clinical and microscopic exam.[5]

Prognosis of those affected by loose anagen hair syndrome is generally good with spontaneous recovery being common and most recovering by adulthood.[1][5]

Complications are few to none. The psychosocial aspect has not been reviewed. The disease is self-limited, resolves with age, and does not require treatment, and complications from the disease process or iatrogenic are minimal.[1][8]

Consultation with a dermatologist may be needed but likely only to establish a diagnosis and distinguish the condition from other causes of non-scarring alopecia in childhood. If presenting as a part of a syndrome, for example, Noonan or neurofibromatosis 1, then appropriate specialists for other organ involvement will be necessary.[1]

• Loose anagen syndrome is an inherited and often self-limited condition resulting in short hair that is easily broken and often does not require cutting.
• Lifestyle modifications that minimize trauma or manipulation of hairs are the best initial form of therapy.
• If treatment is desired topical minoxidil can be tried to lengthen the anagen cycle and reduce shedding.
• The prognosis is generally good with improvement often beginning during adolescence. 

Loose anagen hair syndrome is an inherited disease diagnosed clinically. Poorly adherent anagen hairs result in easy shedding and non-scarring alopecia. It is important to understand the benign, self-limited nature and good prognosis as the disease typically resolves with age. Distinguishing it from other causes of non-scarring alopecia is paramount, and a dermatologist can facilitate this differentiation. Foundations of treatment revolve around minimizing hair trauma and patient reassurance.[8]

Loose anagen hair syndrome is a disease in which diagnosis is made clinically, and treatment revolves around decreasing trauma to easily detached anagen hairs. As the disease process primarily affects young children, pediatricians and pediatric nurse practitioners and physician assistants are likely to be the first to encounter these patients. Awareness of loose anagen hair syndrome and differentials is crucial for diagnosis, and referral to a dermatologist may assist in providing the best patient care. Discussion with parents revolves around lifestyle modification and minimizing trauma to hair with routine combing, washing, and styling. Treatment may be considered with minoxidil applied topically. Biotin or additional nutritional supplementation has not been shown to be helpful.[1][5][8] (Level V)