By Gary M. White, MD
Trichomycosis. This most commonly occurs in the groin or axilla.
Pediculosis. Shown here in the pubic area.
Hair Follicle Nevus
Acquired Progressive Kinking Of Hair
Woolly Hair Nevus
Bubble Hair: Bubble hair is an acquired hair shaft abnormality characterized by multiple airfilled spaces within the hair shaft. It is a result of thermal injury.
Cartilage-Hair Hypoplasia: Cartilage-hair hypoplasia (CHH) is an autosomal recessive metaphyseal chondrodysplasia characterized by short-limbed short stature and fine, sparse hair.
Ectodermal Dysplasias: Alopecia of the eyebrows along with more generalized hypotrichosis, fragile hair, and other findings may occur in both hidrotic and hypohidrotic ectodermal dysplasia.
Hypotrichosis, Hair Structure Defects, Hypercysteine Hair And Glucosuria [BJD 1996;134;319].
Menkes Disease: The hair is short, scanty and hypopigmented. Pili tort may be found.
Monilethrix: The hair shaft is beaded.
Netherton Syndrome: Congenital, exfoliative erythroderma (but not a collodion baby) is the first sign of this disorder. The ichthyosis linearis circumflexa (double-edged scale with a serpiginous border) is usually not seen until after 2 years of age. The diagnosis is confirmed or made by the finding of trichorrhexis invaginata (bamboo hair) of scalp, vellus or eyelash hair.
Pili Annulati: Pili annulati is a rare hair shaft abnormality characterized by alternating light and dark sections of hair visible to the naked eye occurring randomly. It usually occurs as an isolated finding.
Pili Torti: Pili torti (PT) is a rare structural abnormality of the hair in which the hair is flattened and twisted at regular intervals along the long axis. It may occur in isolation or in conjunction with various conditions including Bjornstad's syndrome (with deafness).
Congenital hypotrichosis and Stargardt macular dystrophy characterized by hair loss, macular degeneration, and progressive loss of vision.
(An Bras Dermatol 88:jan/feb 2013)
Trichorrhexis Nodosa: Trichorrhexis nodosa may be diffuse or localized, and congenial or acquired. Clinically, it appears as multiple, tiny, whitish nodes all over the hair. Fracture of the hair shaft gives the appearance of two opposing paint brushes pushing against each other.
Trichorhinophalangeal Syndrome Type I
Trichothiodystrophy: Trichothiodystrophy is an autosomal-recessive genodermatosis with brittle and sulfur-deficient hair. The hair characteristically shows alternating light and dark bands under polarizing light (“tiger tail” banding which is diagnostic). There may be photosensitivity, ichthyosis, brittle hair, intellectual impairment, decreased fertility, and short stature.
See Green Hair
Scalp Hair Heterochromia in a 5-year-old child thought to represent somatic mosaicism [Peds Derm 2014;31;733]. The lighter hair was blond and not white as in poliosis.
Acquired Hypertrichosis Singularis
Median Nasal Dermoid Fistula
Yellowing of the hair is called xanthotrichosis. It may occur from a wide variety of factors including cigarette smoke, copper, picric acid, resorcinol (dihydroxybenzene), and topical medications e.g., anthralin, minoxidil, selenium sulfide and tar shampoo [Dermatology Online Journal 22;6].
Leukotrichia means white hair. The acute change of dark hairs to light in a localized area may occur in vitiligo, alopecia areata and during the regression of nevi e.g., halo nevi [Indian J Dermatol 2016;61:238].
See Graying of Hair
Repigmentation of prematurely gray/white hair has been reported with various medications including latanoprost, lenalidomide, para-aminobenzoic acid, acitretin, etretinate, corticosteroids, cyclosporine, L-thyroxine, verapamil, tamoxifen, levodopa, cisplatin, erlotinib, adalimumab, nivolumab, pembrolizumab, atezolizumab [JAMA Derm 2017;153;1162] and imatinib [Dermatology Online Journal 21;6].
Both lentigo maligna and melanoma may cause localized darkening of hair [JAMA Derm 2016;152;81].
Felting. For a picture, see Indian Dermatol Online J 2015;6:310-1
Uncombable Hair Syndrome
Porphyria Cutanea Tarda