Section 26. Disorders of Nails and Hair

Increased curvature of the nail plate may be due to a wide variety of causes. In this patient, the large, convex nails are a hereditary anomaly and were found to be present in both father and brother. Other causes of clubbing of the nails in children include cyanotic congenital heart disease, cystic fibrosis, and chronic inflammatory bowel disease.

Any skin disease that affects the nail matrix may result in an abnormal nail plate. There are children, though, who only manifest dystrophy of the nail without any other cutaneous lesions, a condition that has been termed twenty nail dystrophy of childhood. The nails have a rough, sandpaper-like quality as well as longitudinal ridging and occasional splitting at the distal nail edge. Similar nail changes can be seen in lichen planus and alopecia areata. In many patients the condition spontaneously regresses.

Trauma to the nail plate or nail folds can produce a wide variety of nail deformities. The one pictured here is the result of a habit tic. This common nail dystrophy is characterized by a longitudinal canal that runs down the center of the entire nail plate. It is caused by manipulation of the proximal nail fold by the index finger of the same hand.

This is a rare condition of unknown etiology that usually involves the thumb. It consists of a canal that runs near the center of the length of the nail plate. Small cracks that extend laterally from the linear canal give the appearance of an inverted fir tree. This deformity tends to resolve spontaneously over a period of months but often recurs.

This is a rare nail disorder that is inherited in autosomal dominant fashion. The color of normal nail plates beyond the lunulae is largely pink from the blood in the blood vessels of the nail bed. The whiteness shown here is due to an abnormality in the nail plate. The nails may also be brittle.

The horizontal white streaks pictured here are the result of abnormal keratinization of the nail plate. The tendency toward leukonychia striata is sometimes inherited in an autosomal dominant fashion. In other cases, it can be attributed to vigorous manicuring, to trauma, or to a wide variety of systemic illnesses. In many patients, there is no obvious cause, and the streaks resolve spontaneously.

This word means separation (-lysis) of nails (onycho-) from nail beds. There are many causes for such a development. The commonest are mechanical. Nails worn long are frequently lifted by being snagged. Excessive soaping and soaking in heavy housework promote separation. The illustration here is of another cause, namely, an idiopathic response by photosensitivity in a patient who had been taking demethylchlortetracycline. Doxycycline also does this.

Many chemicals can discolor nail plates. Solutions of potassium permanganate and silver nitrate stain nail plates brown-purple and jet black, respectively. In the case illustrated here, the stain derived from resorcinol. Such stains are harmless and can be easily removed by superficial scaling with the edge of a glass slide.

Shortly after birth deformity of the great toe, unilaterally or bilaterally, may occur. Thickening of the lateral nail folds and hyponychium with erythema, edema, and sometimes secondary infection may occur. The growth of the nail may protrude through this thickening at its distal end. This condition is sometimes due to congenital malalignment of the nail plates. Surgical treatment is rarely necessary, as the condition is self-limited with good resolution. Secondary infection should be treated if present.

Improper trimming of nails may lead to the formation of an ingrown toenail. The lateral or medial nail fold becomes erythematous, edematous, and painful with the nail growing into the fleshy portion of the folds. Secondary infection and the formation of granulation tissue typically ensue. Surgical treatment is often necessary when local wound care measures fail to alleviate this condition.

These transverse lines or furrows begin at the proximal nail fold and grow out with the nail. They represent a brief interference of nail growth secondary to physical stress such as an illness or nutritional deficiency. The lines are not noticed until several weeks after the precipitating event.

This entity, also known as hereditary osteo-onychodysplasia, is a genetic disease linked to a mutation in the gene encoding transcription factor LMX1B, mapped on the long arm of chromosome 9 (9q34). The manifestations include fingernail dysplasia, absent or hypoplastic patellae, the presence of posterior conical iliac horns, and abnormalities of the radial heads. Patients are also at risk for kidney disease and glaucoma.

The nail change of triangular lunulae is considered pathognomonic (Fig. 26-12). Various other dysplastic nail changes may also be seen. Toenails are rarely affected. Elbow abnormalities include limitation of motion or subluxation of the radius (Fig. 26-13). Absent or hypoplastic patellae may lead to knee pain and instability (Figs. 26-14 and 26-15). Patients should be monitored closely for evidence of kidney involvement.

This is a form of alopecia that is caused by the child's twisting or pulling of his or her own hair. This cause of hair loss is usually easy to recognize. There is often, but not always, a parental awareness of hair-pulling behavior sometimes while the child is studying or watching television or at bedtime. The area of hair loss is usually asymmetric and follows an irregular pattern. Examination of the involved area reveals hair that are broken off at different lengths. There is never the total hair loss of alopecia areata or the scaling and erythema of tinea capitis. In most cases, trichotillomania is evidence of an innocent and benign habit that is best compared to nail biting. However, trichotillomania may sometimes be evidence of more severe emotional distress or a manifestation of obsessive-compulsive disorder. In addition, children who swallow their plucked hair may develop a gastric trichobezoar. The daily application, by the child if possible, of petrolatum to the affected areas is a useful maneuver. It serves as a reminder to stop pulling or twirling, and it makes the hair slippery and hard to pull out.

Another traumatic form of alopecia is due to hairstyles that feature braiding with excessive tension. Figure 26-18 shows hair loss caused by a ponytail. Cornrows or excessively tight braids have a similar effect. The alopecia in this condition is limited to the line of the hair part or to the margins of the scalp. Careful examination reveals broken hair of varying lengths and sometimes a localized folliculitis. The application of heat or of chemicals to straighten hair will also damage the hair shafts and cause traumatic alopecia. An example of this phenomenon is illustrated in Fig. 26-19. For most cases of traumatic alopecia, a change in hairstyle is the only treatment that is required.

The children pictured in Figs. 26-20 and 26-21 are typical of the most common presentation of alopecia areata. There is usually a history of the abrupt onset of hair loss in one or several circumscribed round or oval patches. There is no history of pruritus or scaling. The occasional association of alopecia areata with diseases such as lymphocytic thyroiditis and vitiligo suggests a possible autoimmune etiology. Fortunately, spontaneous regrowth occurs in most patients over a period of 6 months to 1 year. Prognosis is less favorable in patients with more widespread disease and earlier onset. During the initial onset, parents and children should be counseled with cautious optimism but forewarned that progression of the disorder may occur or that it may recur after a period of complete recovery. The use of topical and intralesional corticosteroids or of topical anthralin ointment seems to hasten the resolution of the process.

Illustrated in Fig. 26-22 is ophiasis, a form of alopecia in which hair loss progresses along the margin of the scalp. Figure 26-23 is a severe example of alopecia areata that is progressing toward alopecia totalis. Both ophiasis and extensive alopecia areata carry a poor prognosis for regrowth. The use of intralesional steroids in patients with such extensive disease is extremely painful. Topical agents that cause either an irritant or contact dermatitis of the scalp may sometimes stimulate hair growth. However, they do not seem to affect the tendency toward progression and repeated recurrences in patients with severe involvement. Certainly, alopecia areata has enormous implications for the self-image of the affected child or adolescent. Wigs are sometimes helpful. Patients and families should be advised of the availability of support groups related to this disease.

This is the severest expression of the alopecia areata disease process. Complete loss of scalp hair is termed alopecia totalis. The patient pictured here has also lost all of his eyebrows, eyelashes, and axillary, body, and pubic hair. Hence, alopecia universalis. The prognosis in this situation is particularly poor, with little chance of responding to therapy or of experiencing spontaneous recovery.

This illustration is of regrowth of hair in a patch of alopecia areata. The oddity is that the regrowth was with white hair. The phenomenon is not unusual and is temporary. Eventually the regrowth will be in a color that is normal for the patient. It also frequently happens that regrown hair is temporarily of different texture. In time, assuming no relapse, completely normal color and texture supervene.

This condition may be present at birth but more frequently develops during early childhood. There is absence of hair in the temporal region of the scalp, either on one side or bilaterally. The area of involvement may be either triangular or lancet-shaped. There is no clinical evidence of inflammation or scarring, and there is no known treatment.

This syndrome presents during infancy or childhood with “spun glass” hair. The hair is blond, grows slowly, and is extremely difficult to comb or manage. Subtle longitudinal grooves may be noted on light microscopy and are clearly seen with a scanning electron microscope. Autosomal dominant inheritance is seen in some cases, and the condition may improve as the patient grows older.

This word means “beaded hair” and designates a condition in which the hair varies in thickness along its length. Inheritance is autosomal dominant. The result is that the hair remains dry and brittle and fractures easily. Children with this condition may have normal neonatal hair, but the hair that begins to grow in the second or third month of life will fracture before reaching a normal length. The condition may resolve spontaneously over time or persist into adult life. Keratosis pilaris is almost always associated.

This is another anomaly of hair growth. It is characterized by dry, fragile hair and results in patches of partial alopecia. The second word in the condition's name derives from the presence of whitish nodes along the hair shaft. These nodes are the site of breakage. This disorder is sometimes, though very rarely, associated with argininosuccinic aciduria and mental retardation. The acquired forms are far more common and seem to be the combined result of trauma to the hair and a genetic predisposition.

Use of a hand lens or low-power magnification by microscope reveals the anomalies in the hair shafts. The upper part of the figure shows the hair in monilethrix. The nodes are strung on a thin, internodal shaft. The lower part of the picture shows the distinctive appearance of the hair in trichorrhexis nodosa. The nodes look like brushes or brooms. Breakage of hair occurs at the weak internodes of monilethrix and at the brushlike nodes of trichorrhexis nodosa.

The title means twisted (torti) hair (pili). The gross clinical appearance is of diffuse alopecia and dry, fragile hair. Magnification of hair in this condition reveals spiral twists at irregular intervals along the long axes of the shafts. Pili torti is seen in association with a number of enzyme deficiencies and hereditary syndromes, including citrullinemia and Bazex syndrome. It may also be associated with sensorineural hearing loss. No effective treatment is available.

Dramatic thinning of the hair is usually noted during early childhood. Some cases are familial, and affected siblings appear to have blonder and thinner hair than family members who are unaffected by the disorder. A hair pull examination reveals easily plucked hair that are in the anagen phase. Microscopic examination of pulled hair reveals the “rumpled sock” appearance of an abnormal hair bulb (Fig. 26-34). In many patients, the hair thinning improves with age.

The term trichothiodystrophy describes brittle hair with an abnormally low sulfur content. There are different syndromes that have trichothiodystrophy as a feature along with other findings including intellectual impairment, decreased fertility, short stature, ichthyosis, and photosensitivity. The hair is short, sparse, and brittle (Fig. 26-35). Examination of the hair shaft under polarizing light microscopy reveals alternating light and dark bands giving the hair a “tiger-tail” appearance (Fig. 26-36). The disorder is transmitted in an autosomal recessive fashion. It is unknown whether the different syndromes that have trichothiodystrophy as a feature are distinct entities or represent a single variable syndrome.

Illustrated here is a hamartoma consisting entirely of hair follicles. A small lesion of this type is completely benign and unimportant. The presence of a patch of hypertrichosis overlying the mid-lower back, however, may be an indication of a significant underlying neurologic abnormality. The so-called faun tail nevus may signal the presence of spina bifida occulta, diastematomyelia, or duplication or tethering of the spinal cord. A thorough neurologic investigation is warranted in such cases.

This term is sometimes used to denote the presence of localized hypertrichosis in the lumbosacral region. The presence of this hair tuft may signify the presence of an underlying spinal dysraphism, such as spina bifida occulta or a tethered spinal cord. CNS lesions of this type may eventually lead to a neurologic defect and require neurosurgical correction. The simultaneous presence of other skin lesions, such as lipoma, hemangioma or port-wine stain, increases the possibility of a spinal cord abnormality.

Scalp skin sometimes develops redundantly as a congenital anomaly or in association with a disease such as acromegaly. The consequence is furrowed wrinkling of hyperplastic skin in a pattern that suggests the puzzled pate of a bulldog, in whom the condition is natural. There are cases that are so extreme that hygiene of the scalp is difficult and the cosmetic appearance justifiably disturbing. Plastic surgery is a reasonable treatment.