Acquired Progressive Kinking of the Hair (APKH)

Acquired Progressive Kinking of the Hair (APKH), is a rare disorder characterized by dull, frizzy, extremely curly scalp hair. The syndrome was first described in 1932 and since that time, only a couple dozen cases have been reported and even fewer have been thoroughly studied.[1]

What we do know is that the syndrome is acquired around adolescence, which is one of the factors that distinguishes it from conditions such as pili torti and woolly hair naevus, which occur at birth or infancy. The earliest documented case of APKH was in an 8-year old girl and the latest onset was in a 23-year old man.[2]  The frizzy, kinky hair appears in the frontal, temporal, and vertex regions (frontal, parietal, occipital) of the scalp.

An electron microscopic examination of at least one case of affected hairs showed partial twisting of the hair along its longitudinal axis along with longitudinal grooves in the hair shaft (pili canaliculi)[3]. In addition to the severe kinking of the hair, the follicles may turn lighter (hypopigmented), darker (hyperpigmented) or remain the same color. Hair growth may or may not be affected by the kinking.

A proposed criteria for diagnosis of APKH published in the Journal of Pediatric Dermatology (Vol 21, No. 3 265–268, 2004) includes:

An acquired circumscribed area of dull, woolly, hair in the frontal,

temporal, or parietal regions in the absence of previous trauma.

Irregular, twisted, and tortuous hair with the first twist appearing

at 3–4 cm from the emergence of the hair.

On optical microscopy, a periodic reduction in the hair shaft diameter

with broadened sections alternating with flattened ones.

On scanning electron microscopy, partial twisting of the hair on its

longitudinal axis with a 180-degree rotation, variable pili canaliculi

(or longitudinal grooves), spindle-shaped broadening with

occasional fractures, and increased numbers of cuticular cells per

diameter in the twisted sections.[4]

            Some scientists suggest that the onset of APKH may be a type of androgenic alopecia, the most common form of hair loss that results from a genetic predisposition making follicles sensitive to the effects of dihydrotestosterone (DHT). Androgenetic alopecia is often termed “male pattern baldness,” but women can suffer from it, too. In men, the hair loss usually begins above the temples and thins at the crown. In women, the hair loss usually occurs along the hair part. The hair loss occurs as a genetic condition related to the presence of androgens in the blood. Androgens are hormones responsible for normal male sexual development as well as regulating hair growth and sex drive in both men and women.[5]

In one study published in the Archives of Dermatology, the patients (7 males), all had a strong family history of androgenic alopecia. In addition “the pathological features of the affected scalp were consistent with the diagnosis of the early stages of androgenetic alopecia.” [6] All cases eventually evolved into androgenetic alopecia within a two to nine-year period, and 5% Minoxidil was ineffective in preventing the eventual hair loss. The effects of finesterinde (Propecia) have not been recorded in cases of APKH.

APKH appears to share several characteristics of androgenic alopecia[7]:

• APKH occurs at the onset of puberty when hormones are at their most active.
• There is an increased concentration of DHT on the scalp.

DHT stands for dihydrotestosterone, a potent androgenic hormone synthesized in the prostate gland, hair follicles, testes and adrenal glands by 5-alpha reductase, an enzyme involved in steroid metabolism. If hair follicles are genetically sensitive to DHT, hair follicles can shrink and growth can slow or stop altogether.

• The affected hairs appear similar to pubic hair.
• The distribution of affected hair is similar to pattern baldness.
• In some patients, APKH developed into androgenic alopecia.
• There is a decreased anagen to telogen ratio.

Another cause of APKH may be the use of retinoids such as Isotretinoin (Accutane), used for severe acne, and Etretinate, prescribed for psoriosis.[8] Both drugs have shown to produce kinking of hair in some people, which may reverse itself with the cessation of the drug treatment.

APKH is very similar to “Whisker Hair,” a condition where scalp hair develops into short, curly, dark hair similar to beard hair.[9] Some scientists even believe that “Whisker Hair” and APKH are variants of the same disorder because both can lead to excessive hair loss.[10]

      Still other experts believe APKH may be an autoimmune problem.[11] To lend further to the lack of solid conclusions, some APKH patients have reported  progression of symptoms over time, while still others report regression, as in the case of at least one woman whose symptoms disappeared with the onset of pregnancy.[12] Researchers at the University of Bologna who published a study in the Archives of Dermatology (Vol. 135, No. 10, Oct. 1999) even concluded that APKH was not its own syndrome, but rather the term Acquired Progressive Kinking of the Hair “encompasses a number of conditions characterized by acquired curling of the scalp hair.”[13]

Clearly, more cases of APKH need to be recorded and studied in order to learn whether it has specific common symptoms and how it can be treated.

Notes

[1] Pediatric Dermatology, Acquired Progressive Kinking of the Hair, http://onlinelibrary.wiley.com/doi/10.1111/j.0736-8046.2004.21317.x/pdf, p. 265

[2] Pediatric Dermatology, Acquired Progressive Kinking of the Hair, http://onlinelibrary.wiley.com/doi/10.1111/j.0736-8046.2004.21317.x/pdf, p. 266

[3] Pediatric Dermatology, Acquired Progressive Kinking of the Hair, http://onlinelibrary.wiley.com/doi/10.1111/j.0736-8046.2004.21317.x/pdf, p. 265

[4] Pediatric Dermatology, Acquired Progressive Kinking of the Hair, http://onlinelibrary.wiley.com/doi/10.1111/j.0736-8046.2004.21317.x/pdf, p. 267

[5] Wikipedia.org, Androgenic Alopecia, http://en.wikipedia.org/wiki/Androgenic_alopecia

[6] Archives of Dermatology, Acquired Progressive Kinking of the Hair, http://archderm.ama-assn.org/cgi/content/abstract/135/10/1223

[7] Pediatric Dermatology, Acquired Progressive Kinking of the Hair, http://onlinelibrary.wiley.com/doi/10.1111/j.0736-8046.2004.21317.x/pdf, p. 266

[8] The Trichological Society, http://www.hairscientists.org/kinking.htm

[9] PubMed.gov, Whisker Hair, http://www.ncbi.nlm.nih.gov/pubmed/7238115

[10] Pediatric Dermatology, Acquired Progressive Kinking of the Hair, http://onlinelibrary.wiley.com/doi/10.1111/j.0736-8046.2004.21317.x/pdf, p. 267

[11] The International Association of Trichologists, Hair Shaft Problems, p. 95.

[12] Dawber, Diseases of the Hair and Scalp, p. 292.

[13] Archives of Dermatology, Acquired Progressive Kinking of the Hair, http://archderm.ama-assn.org/cgi/content/abstract/135/10/1223

Sources

Archives of Dermatology, Vol. 135, No. 10, Oct. 1999, Acquired Progressive Kinking of the Hair, http://archderm.ama-assn.org/cgi/content/abstract/135/10/1223

Dawber, Rodney, Ed., Diseases of the Hair and Scalp, Third Edition, 1997.

Pediatric Dermatology, Acquired Progressive Kinking of the Hair, Vol. 21, Issue 3, May 2004, http://onlinelibrary.wiley.com/doi/10.1111/j.0736-8046.2004.21317.x/abstract

The International Association of Trichologists, Hair Shaft Problems, 1999.

The Trichological Society, http://www.hairscientists.org/.

---