Acquired Progressive Kinking

Sometimes referred to as 'whisker hair' presents as a development of coarse short and often kinky hair at the occipital and auricular margins contemporaneously with the onset of early androgen related alopecia.
In some individuals hair-shafts develop a progressive tendency to kinking in patches, thus producing a woolly appearance.
This it has been suggested may be due to localised scalp damage associated with chemical processing.
Colour change (yellow green) maybe an accompanying feature.
Fragmentation and fracturing of the cortex may occur as trichorrhexis nodosa, and/or trichoptilosis.

Acquired progressive kinking of the scalp hair (APKH) described by Wise and Sulzberger in 1932 appears to be rare. However many cases may not be recorded.
It may be synonymous with 'whisker hair' although this is typically around the ears of males and not necessarily in the distribution of APKH.
It has been confused with the 'woolly hair naevus' but APKH is differentiated clinically by its onset in adolescence or adult life.

Progressive extension has been reported over a period of years but in a series of three women regression has also been seen - one in association with pregnancy.

Aetiology and pathology

The aetiology of APKH is unknown; there is as yet no evidence that it is genetically determined, although if it is connected with androgenetic alopecia it must in some sense have an inherited component. The hairs in the affected region of the scalp may show both structural and functional abnormalities including irregularly distributed kinks and half-twists. However Mortimer detected no pathological features in scalp biopsy.
The duration of anagen is reduced.

The use of systemic retinoids has produced a new group of patients with APKH. Isotretinoin and Etretinate produce reversible diffuse kinking of hair (with no change in pigment) in some individuals. It does not appear to be dose dependent.

Microscopically, hairs may demonstrate half-twists and slight changes in bore, with normal cuticle.
Retinoids are also recognized as a cause of reversible hair loss, which experience suggests is dose related. It is not clear whether the relationship between hair loss and APKH is the same for those taking retinoids as it is proposed to be for those suffering the natural course of the condition.

Clinical features

The patient gradually becomes aware that the hair in one region of the scalp is becoming darker, kinkly and that a progressive change in texture is accompanied by a decreased rate of growth, as a result of which they rarely require cutting. On examination the hair on one or more regions of the scalp is wiry, kinky, unruly, dry and lusterless. There are no sharply defined boundaries between normal and abnormal hair. In some of the cases described, acquired kinking preceded development of common male pattern alopecia.