Adamson's fringe is located at the upper margin of the keratogenous zone of the hair follicle where the nucleated hair shaft cornifies completely and gets converted to hard anucleated keratin.
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| Adamson's fringe |
It marks also the area of complete keratinization of the cuticle and Henle's layer of the inner root sheath and the beginning of the stem of the follicle. In Tinea capitis, dermatophytic infection of the hair shaft is restricted to this zone and the fungi do not penetrate further down the infected hair in the bulb of the follicle. The fungi in Adamson's words form “a fringe of mycelium surrounding the hair shaft and project below the lower margin of the sheath of spores around the root-stem.”
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| Photomicrograph at level of Adamson's fringe, showing on the right the covering inner root sheath with bright pink trichohyalin granules, and in the centre, mainly anucleate hair shaft with few residual nuclei |
The keratogenous zone of the hair follicle is a broad area above the bulb of the follicle in which the cells are gradually transformed into hard keratin of the hair shaft.
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These cells maintain their nuclei, but exhibit cytoplasmic changes as they convert from nucleated to anucleated hard keratin. This zone is shaped as a high arched curve (inverted V shape) which ends at a discrete border commonly known as Adamson's fringe. This forms the boundary between nucleated cells of a hair in the bulb of a follicle and anucleated cells of a hair in the stem of a follicle.
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| Photomicrograph of V.S of hair follicle showing transition of nucleated hair shaft to anucleated structure at Adamson's fringe |
Adamson's fringe is an important anatomical and functional landmark in the hair follicle and it is at this region that the following changes are noted:
- The bulb of the follicle gives rise to the stem of the follicle, which extends from Adamson's fringe to the lower part of the isthmus of the follicle.
- The corneocytes of the nucleated hair shaft lose their nuclei and get completely keratinized.
- The cuticle and Henle's layer of the inner root sheath get fully cornified with loss of their trichohyalin granules.
- Huxley's layer of the inner root sheath starts losing its trichohyalin granules at this level and begins to cornify, with complete cornification of it occurring midway up the stem with the formation of blue-gray compactly arranged corneocytes.
Histologically, a helpful morphological marker to recognize Adamson's fringe are artifactual clefts that form between the inner root sheath about to cornify and a hair about to do the same.
Clinically this area is important as fungal (dermatophytic) infections of the hair (Tinea capitis), cannot descend below this level into the bulb of the follicle, and as Kligman showed, this is the zone where the hair shaft is penetrated by fungal hyphae.
Horatio George Adamson, a distinguished dermatologist and doyen of British Dermatology was born in London on November 28, 1865. After schooling in London, he joined St. Bartholomew's hospital in 1883 with a scholarship, and graduated as M.B of London, in 1889. Three years later he got the M.D, and was awarded the M.R.C.P in 1903 and the F.R.C.P in 1911.
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| Horatio George Adamson |
His initial exposure to clinical medicine was mainly in pediatrics having worked at Paddington Street Children's hospital and the North East Hospital for children till 1893 when he joined J. J. Pringle as assistant in the skin department at Middlesex hospital (Pringle had in 1890 described Adenoma Sebaceum, eponymically named after him).
At Middlesex hospital under Pringle, Adamson developed interest in dermatology and in the 3 years that he spent there worked on ringworm and published several articles. His first publication was a translation of Leloir's Dermatological Neuroses and their Treatment in the British Journal of Dermatology in 1894. Three papers on studies on ringworm followed in 1895 and 1896, when he observed and described the phenomenon of dermatophytic infection of hair unable to descend below a narrow area at the upper margin of the keratogenous zone with formation of a fringe of mycelium at that level, which later was named after him and is now familiar to us as Adamson's fringe. One of these papers was read at the 3rd International Congress of Dermatology, held in London in 1896.
In his original description, Adamson stated, “the whole root-stem of the hair is surrounded by a sheath of closely placed small spores, extending from a short distance above the intrafollicular portion to the junction of the root stem with the soft root bulb. There is no mycelium on or in the bulb, but at the neck of the bulb, just at its junction with the root-stem, there is a fringe of mycelium surrounding the hair and projecting below the lower margin of the sheath of spores around the root-stem.”
Having married Mabel Draper in 1896, Adamson left London to settle down in General Practice at Guildford, in the county of Surrey, where he remained for the next 7 years. His interest in dermatology however seems to have continued as he accepted positions while still in General Practice which enabled him to see patients with dermatological diseases. He was Honorary Asst. Medical Officer at the Royal Surrey County Hospital and in 1901 joined the Broom House School for ringworm.
Moving back to London in 1903, he decided to specialize in dermatology, and on the advice of Pringle was assistant to T. Colcott Fox at the Westminster Hospital. He had the greatest affection for Colcott Fox and admiration for his remarkable powers of observation and diagnosis, powers which Adamson himself developed in no small measure. In 1908 he was appointed as Radiologist for ringworm cases at the Metropolitan Asylum Board School at Sutton and this experience stimulated him to devise a modification of Kienboeck's method of X-ray epilation of scalp hair for treatment of scalp ringworm which reduced the time of treatment from 5 h to 1.5 h. This method was published in Lancet in 1909 and was used the world over.
He moved to his Alma Mater, St. Bartholomew's hospital as chief assistant to J. A. Ormerod and by 1909 when the skin department there had been made into a full fledged department he was the physician to the skin department which he later headed till he retired in 1928. His experience in X-ray therapy of skin diseases made it possible for him to obtain for the skin department its own X-ray unit which was the envy of all skin departments in other hospitals as they had to refer their patients to the departments of radiology. (X-ray treatment of skin diseases was common in those days with radiation used for treatment of hair epilation for Tinea capitis and in the treatment of Lupus vulgaris.)
He was the Goulstonian lecturer at the Royal College of Physicians of London in 1912, his subject being ‘Modern views upon the significance of skin eruptions.’ In 1922-23, he was the President of the section of dermatology of the Royal Society of Medicine and in 1924 was the President of the British Association of Dermatology and Syphilology.
He was a prolific writer and with his earlier experiences in pediatrics published in 1907 an excellent book on “Skin affections of childhood.” In 1911, he wrote eight chapters on dermatological subjects in Allbutt and Rolleston's “System of Medicine” and on X-ray treatment of skin diseases in the Dictionary of Treatment. More than 70 other papers were published by him between 1894 and 1949, his principal interests being, skin diseases in children, ringworm, other fungal infections, Lupus vulgaris, eczemas and infections due to Staphylococcus and Streptococcus.
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