| Woolly hair | |
| Symptoms: | Hair: difficult to brush, tight locks, short, lighter colour |
| Onset: | Birth, infancy |
| Types: | Familial, hereditary, woolly hair nevus |
| Management: | --> |
| Prognosis: | May improve with age |
| Frequency: | Rare |
Woolly hair is a difficult to brush hair, usually present since birth and typically most severe in childhood.[1] It has extreme curls and kinks, occurs in black people and is distinct from afro-textured hair.[2] The hairs come together to form tight locks, unlike in afro-textured hair, where the hairs remain individual.[1] Woolly hair can be generalised over the whole scalp, when it tends to run in families, or it may involve just part of the scalp as in woolly hair nevus.[3]
The presence of woolly hair may indicate other problems such as with the heart in Naxos–Carvajal syndrome.[4] Diagnosis is suspected by its general appearance and confirmed by scanning electron microscopy.
The condition is rare.[1] Alfred Milne Gossage coined the term woolly hair in 1908. Edgar Anderson distinguished woolly hair from afro-textured hair in 1936.
Alfred Milne Gossage coined the term woolly hair to describe the sign in 18 members in three or four generations of a European family in Lowestoft, England, in 1908.[5] [6] He thought it resembled afro-textured hair, possibly from a Mexican ancestor in that family.[6] He described a dominant inheritance in several members with thick skin of palms and soles, curly hair, and two different coloured eyes, and sent them to William Bateson.[7] Edgar Anderson distinguished woolly hair from Afro-hair in 1936.[8] In 1974 Hutchinson's team classified woolly hair as hereditary woolly hair (autosomal dominant), familial woolly hair (autosomal recessive), and woolly hair nevus.[3] Woolly hair was found in Naxos syndrome, first described in 1986 in Naxos, Greece, and was noted in Carvajal syndrome, first described in 1998, in Ecuador.[4]
Woolly hair may run in families and either occur on its own, or as part of a syndrome.[4]
Hereditary woolly hair is autosomal dominant.[3]
Familial woolly hair is autosomal recessive.[3] It may be part of a syndrome such as Naxos syndrome, due to passing on of mutations in the JUP gene.[4] When part of Carvajal syndrome, it is due the passing of mutations of the Desmoplakin gene.[4] The two syndromes caused by two different genes, are considered as one entity; Naxos–Carvajal syndrome.[4]
The woolly hair of a woolly hair nevus is in a circumscribed area of the scalp, appears in infancy and does not run in families.[3] It likely represents a mosaic RASopathy.[3]
Woolly hair is typically very curly, kinky and characteristically impossible to brush.[1] [2] It can be generalised over the whole scalp, or involve just part of the scalp, and occurs in non-black people.[1] [2] The hairs come together to form tight locks, whereas in afro-textured hair the hairs remain individual.[1] The hairs typically remain shorter than and may be slightly lighter in colour.[1] [3]
Woolly hair nevus is a localised area of woolly hair, which may occur on its own, or appear as dark twisted and kinking hair in an adult.[3] Half of people with woolly hair nevus have a warty skin lesion on the same side of the body.[3] It may be associated with eye problems such as two different coloured eyes or strands of tissue across the pupil of the eye.[3] Other associations include ear problems, kidney disease, tooth decay, impairment of bone growth, and skin lesions.[3]
Generalised woolly hair is typically seen in Naxos–Carvajal syndrome (with heart involvement),[4] Noonan syndrome, and cardiofaciocutaneous syndrome.[3] [4]
Diagnosis is suspected by its general appearance and confirmed by scanning electron microscopy.[9] Microscopy, trichoscopy and dermoscopy also play a role.[3] The hair strand typically has a smaller diameter, is ovoid on cross-section and exhibits abnormal twisting.[1] [3] The hair shaft also has weak points and alternating dark and light bands.[1] The hair shaft is characteristically of a "snake crawl appearance".[3] Dermoscopy may be required to recognise skin signs.[3]
The condition may improve in adulthood.[1]
The condition is rare.[1]