Each year there are approximately 2 to 2.5 cases per million people with loose anagen hair syndrome. Causes
The main pathological cause of loose anagen syndrome is the absence or insufficient amount of the inner root sheath in the anagen staged hairs. This creates a gap in the linking between the inner root sheath and the hair cuticles. Both of these hair features stimulate hair growth but with this detachment in the linking, loose anagen hairs are not able to grow to a long length. The abnormalities caused by the inner root sheath creates disruption in the support and anchoring of the anagen hairs. Patients with loose anagen hair syndrome have mutations in the protein keratin K6HF, which is located in the middle of the hair shaft and inner root sheath, the companion layer. These mutations account for the phenotypical features of loose anagen syndrome. In the Huxley cells of the inner root sheath of abnormal anagen hairs, there is the formation of vacuoles and the build-up of fluid which is not usually seen. There are also dyskeratotic modifications in the Henle cells, as well as the cuticle cells in both the inner root sheath and hair shaft. The hair shaft has been reported as thin for some cases and normally structured for other loose anagen syndrome reports. The inner root sheath of normal anagen hairs usually do not have keratin in the Huxley cells, Henle cells and inner root sheath.
They are usually organised in an orderly manner and densely compacted.Genetics is one of the causing factors of loose anagen syndrome. It has been studied that this hair condition is autosomal dominantly inherited. Diagnosis
Patients with loose anagen syndrome do not report the same hair abnormalities. Loose anagen syndrome is usually diagnosed after taking into consideration the physical examination, clinical history and a microscopic examination of the hairs of the patient. Some patients visit a dermatologist for diagnosis and to distinguish between loose anagen hair syndrome and other conditions that it can be misdiagnosed for.A pull test is performed in order to diagnose a patient with loose anagen hair syndrome as one of the characteristics of this hair condition is hair that is easily removed from the scalp. A group of around 40-60 hairs, that are attached to the scalp, is pulled in a clement manner. The patient will be diagnosed with loose anagen syndrome if great amounts of hair is detached from the head. If at least 50% of the hairs removed is at the anagen hair stage, the outcome of the pull test is positive. The detachment of only 4-6 hairs is considered a normal outcome, as approximately 10% of the hairs on the scalp are at the telogen stage. The removed loose anagen hairs are not fragile and are of normal tensile strength.In an electron microscope image of a loose anagen hair, deformities such as grooves, curls and ridges are visible in the hair shaft, which is made from keratin.