ACQUIRED PROGRESSIVE KINKING
(syn: symmetrical circumscribed allotrichia)
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 Hair
Inga Zemite MD MTTS
1.1. Introduction.
Acquired Progressive Kinking of the Hair (APKH), (synonyms: symmetrical circumscribed allotrichia) is a disease where clinically tight, short and curly hair in an otherwise normal scalp appears in circumscribed regions, usually in the frontal and temporal areas and vertex regions of the scalp as well as the supra-auricular and post auricular margins. Occasionally, all scalp hair may be involved. There is a tendency for affected hairs to change its texture, color is darker than normal and they become unruly and rough in appearance.
APKH has its onset at or after puberty. It encompasses a number of conditions characterized by acquired curling of the scalp hair. Acquired hair kinking on the androgen-dependent areas of the scalp represents a modality of onset of androgenetic alopecia associated with poor prognosis.
1.2. History and Epidemiology.
APKH was first described by Wise and Sulzberger in 1932. It is a rare condition, there are only about 20 cases reported. It may be related with low diagnostic of this condition.
There is a view, postulated by Mortimer and coauthors in 1985 and recently supported in the article by Boudou and Reygagne; that APKH is not a separate entity but a variety of androgenetic alopecia. This view is still controversial.
Males are affected more often as females.
The term acquired progressive kinking of the hair has been used in the literature to describe rather different conditions. These include:
2.1. Kinking of the hair over the peri auricular areas of the scalp (whisker hair). Whisker hair is short and curly and resembles a continuation of the beard. According to Norwood, whisker hair is strongly associated with severe androgenetic alopecia and typically affects young men (aged 18-25 years) who will rapidly develop extensive baldness.
2.2. Acquired progressive kinking of androgen-dependent hair associated with hair thinning. All reported patients were post pubertal males and developed androgenetic alopecia of the areas affected by hair kinking.
2.3. Rapidly progressing kinking almost of all the scalp hair without associated hair thinning. In these cases, kinking has a rapid onset, quickly progresses to involve the entire scalp, and persist unchanged during the years. This variety of acquired hair kinking affects both androgen-dependent and non–androgen-dependent scalp follicles and is not associated with hair thinning.
2.4. Acquired reversible hair kinking before or after puberty. In these patients, hair kinking completely regresses with time and is not associated with hair thinning.
2.5. Acquired hair kinking involving a localized non–androgen-dependent area of the scalp. In all patients, the condition remains stable in the follow-up period, affects non–androgen-dependent follicles, and is not associated with hair thinning. This variety of APKH may clinically resemble woolly hair nevus, but it is acquired and not congenital.
In addition, a few patients described in the literature who were diagnosed as having APKH were actually affected by diffuse partial woolly hair. This condition is characterized by the presence of 2 distinct hair populations (straight hair and curly hair) that are contemporarily present and intermingled.
In types 3, 4, and 5 APKH, hair kinking is not restricted to androgen-dependent areas and does not lead to hair thinning. These types of hair kinking have been observed in women as well as in pre-pubertal patients.
In types 1 and 2 APKH, development of curly hair characteristically heralds the onset of androgenetic alopecia. These types of APKH typically affect young males with a strong family history of androgenetic alopecia.
1.3. Pathogenesis
The etiology of APKH is unknown. Its connection with androgenetic alopecia must in some sense prove its inherited component, but still there is no evidence that it is genetically determined.
There were showed pathological features consistent with the diagnosis of androgenetic alopecia as well as were found increased scalp concentrations of dihydrotestosterone in a patient affected by this condition. Group of patients had strong family history for androgenetic alopecia also.
Why hair thinning may cause kinking is not known, since factors determining the different hair shapes are not completely understood. Factors that may be implicated include
1) change in the shape of the hair follicle during miniaturization,
2) irregularities of mitosis within the hair bulb, and
3) changes in the arrangement of the keratin filaments within the hair shaft.
The use of systemic retinoids is claimed to contribute APKH. Isotretionin and etretinate can produce reversible, diffuse kinking of hair with no change in pigment in some individuals. 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.
1.4. Clinical features.
Patients notice a change in the shape and texture of the hair in the frontotemporal region and gradually become aware that the hair in one region of the scalp is becoming darker, kinky and that progressive change in texture is accompanied by a decreased rate of growth.
The hairs in the affected region of the scalp can show both structural and functional abnormalities. On examination the hair on one or more regions of the scalp is wiry, frizzy, dry and lusterless. Hairs are finer or coarser then in the unaffected scalp, and they show irregularly distributed kinks and half-twists. The area of hair kinking is easily distinguishable from the surrounding scalp. The color of the hair in the affected area can be darker or lighter than the surrounding hair or has not any color changes at all. Sometimes a mild hair thinning can be seen of the frontal area as compared with the occipital scalp.
The family history for androgenetic alopecia often is positive while for APKH - negative. Patients usually are in good health.
One can observe progressive expansion over a period of years but regression has also been seen, one case of regression is described in association with pregnancy.
1.5. Laboratory investigations and Pathology.
A pull test, a trichogram and biopsy can be performed from the affected and nonaffected scalp.
5.1. Pull test can show extraction of about 5-12 telogen hairs.
5.2. The hair samples for trichogram have to be taken 5 days after shampooing. The trichogram from affected scalp usually reveals a decreased anagen to telogen ratio. Microscopically, hairs may demonstrate half-twists and slight changes in bore, with normal cuticle. Hair shaft examination do not show signs of hair weathering but only irregular torsions of the hair shaft along its major axis. In these areas, the hair shaft gives the impression of being thinned, but this was only a consequence of torsion. (Tosti at all.)
5.3. For investigation a 5-mm punch biopsy sample can be obtained. As described in study made by Tosti at all the average total number of hairs in horizontal sections of the 5-mm punch biopsy specimens taken from the affected scalp were 40. Mean terminal hair to vellus hair ratio was 3.4:1, with 85.5% anagen and 14.5% telogen. Sections taken from the occipital scalp in 2 patients (from 7 observed) showed 45 hairs in one patient and 42 hairs in the other. Terminal to vellus ratio was 12:1 and 18.5:1, respectively. Two specimens showed a slight superficial perivascular lymphocytic infiltrate in the papillary dermis with a moderate amount of mucin between collagen bundles. Infundibular plugging and bacteria were also evident.
However, there are no abnormalities and no pathological features detected in hair shaft on scalp biopsy.
1.6. Differential diagnosis.
There are some similar conditions that are misdiagnosed as APKH and have to be differentiated.
6.1. APKH is similar to whisker hair, but can be differentiated as this condition is typically around the ears and not necessarily in the distribution of AKPH;
6.2. it has been confused with the woolly hair nevus, but AKPH has its onset in adolescence or adult life;
6.3. the differential diagnosis includes inherited forms of kinky hair and
6.4. kinky hair secondary to mechanical, chemical, or traumatic manipulation.
1.7. Treatment.
Treatment with topical minoxidil is used but does not always prevent development of hair thinning in the scalp areas affected by hair kinking neither development of androgenetic alopecia.
There are no data about the effects of finasteride in APKH, although increased scalp and serum levels of dihydrotestosterone have been reported in patient with this condition.
Appropriate hair cosmetic usage can be advised to these patients for better coping with condition.
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Observations by Sajjad Ahir M.D. LTTS (Consultant Dermatologist)
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.
Sajjad Ahir M.D. LTTS (Consultant Dermatologist)
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