Loose anagen syndrome (LAS) is a hair disorder in which the hair is ‘loose’ and can be painlessly pulled from the scalp. Essentially, hairs are not anchored into the scalp properly with no known cause; as a result affected patients have a ‘bed head’ appearance and hair that doesn’t seem to grow. Most often this hair disorder has been classically described in children, predominately blonde girls, though this condition has even been reported occasionally in adults. However, recent literature has suggested that a diagnosis of LAS should be considered in all children of all skin types who have characteristic features. There is some evidence that LAS is possibly an inherited condition, but this has not been confirmed.
LAS should be suspected in people with sparse fine hair that is able to be painlessly removed from the scalp without effort, and often tangled hair at the back of the head. There is no inflammation or scarring present on the scalp. Diagnosis is made is made by microscopic examination of pulled hairs. This shows ruffled hair cuticles (outer layer of hair), sometimes described as a rumpled sock or hockey stick, which differ from the normal smooth and straight cuticles in unaffected patients. Rarely, even the eyebrow has been reported to be affected by LAS.
LAS has been categorized into 3 groups: LAS type A presents with sparse, short hair. LAS type B presents with curly, sometimes patchy hair that is difficult to control. LAS type C is the adult type, where hair presents with normal thickness, but falls out excessively. The diagnosis of LAS can often be mistakenly confused with other conditions of hair loss including alopecia areata, telogen effluvium, and trichotillomania. By using a patient’s history and looking at the hair under a microscope, a dermatologist can prevent this confusion and avoid unnecessary treatments.
LAS has a known association with Noonan Syndrome, a congenital syndrome that includes heart defects, short stature, learning difficulties, and other characteristics. Other than Noonan Syndrome, no additional diseases have been shown to be strongly associated with LAS. Though a relationship with atopic disorders (asthma, allergies, and atopic dermatitis) has been suggested, it has not been confirmed because these conditions have been increasing in prevalence in recent years.
LAS is typically considered a benign condition that will resolve in time. However, some cases of persistent LAS have been reported for up to 14 years. One treatment for this condition beyond watchful waiting is to recommend biotin supplements, though no data has shown this to be a scientifically supported treatment. Nevertheless, the only required treatment for LAS is reassurance that the condition is benign and addressing cosmetic concerns within reason.
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