Uncombable hair syndrome - Hair and Scalp
On microscopic examination, the hair shaft has characteristic irregular twists along its axis at regular intervals. These irregular twists are what makes the hair difficult to comb and prevents the hair from grouping with adjacent hair in an organized fashion, contributing to the unruly appearance. It also has triangular to reniform shape on cross section, with longitudinal grooves along the entire length of the hair shaft. The cause of the malformed hair has been attributed to an altered inner root sheath that then gives rise to an abnormal hair shaft.
Familial cases occur and show autosomal dominant inheritance with incomplete penetrance. Recessive forms exist, with variable penetrance, and sporadic cases have also been reported. There are also acquired and partial variants. The acquired form presents later in life and is more common among individuals with dark and/or curly hair. The partial variant is confined to a well-demarcated area of hair on the scalp with the characteristic features of uncombable hair syndrome.
Associated features of ectodermal dysplasia have been reported in some cases.
L67.8 – Other hair color and hair shaft abnormalities
254230001 – Uncombable hair syndrome
Differential Diagnosis & Pitfalls
- Pili annulati
- Loose anagen syndrome
- Pili torti
- Woolly hair
- Drug-induced kinking
- Loose anagen hair syndrome of childhood