Concomitant presentation of alopecia areata in siblings: a rare occurrence.

Alopecia areata (AA) is one among the many causes of non-scarring alopecia in children. Family history has been noted in 10-20% of cases, but concomitant presentation in siblings is extremely rare. The patterns and associations of childhood AA are similar to adults; however, there are some differences which are being highlighted in this article.

INTRODUCTION

Non-scarring alopecia in children often poses a diagnostic dilemma for the dermatologist. Alopecia areata (AA) is one among the causes of non-cicatricial alopecia in children which comes next only to non-inflammatory tinea capitis and telogen effluvium. Though it affects all age groups, authentic statistical data regarding the condition in pediatric age group are lacking. AA is considered to be of autoimmune etiology affecting hair follicles and nails in genetically predisposed individuals.[1] A rare occurrence of concomitant AA in two siblings is presented in this article along with the special aspects of AA in children.

CASE REPORT

Two siblings aged three and five years were presented to the outpatient department with complaints of asymptomatic patchy alopecia of the scalp of six- and three-month duration, respectively. Their father was a daily laborer and the family has recently migrated from north India. There was no history of similar illness among the family members. The physical examination suggested grade three malnutrition in the girl and grade one in the boy. Systemic examination of the children was within normal limit. Scalp examination of the girl showed multiple circular patches of non-scarring alopecia [Figure 1a] with exclamation mark-shaped hairs near the periphery. The male sibling was having two diffuse patches of decreased hair density with ill-defined borders along with easy pluckability of hair [Figure 1b]. The affected scalp was soft and smooth in both the cases. The nails of the boy showed shallow pitting. There was no other patchy hair loss anywhere on the body. Features of atopy were absent. A provisional diagnosis of patchy and reticulate type of AA was made for the girl and the boy, respectively. Hematological and biochemical investigations were normal in both the children. Light microscopy of the hair roots showed predominantly dystrophic hair showing tapered roots with absent root sheath. Few telogen hairs were present. Most of the hairs were lighter in color with decreased shaft diameter. Thyroid function tests were done for both the kids including autoantibody profile for thyroid which were found to be normal. Histopathological examination of the scalp confirmed the diagnosis which showed peribulbar lymphocytic infiltration with reduction in the number of hair follicles. Topical tacrolimus 0.03% ointment was prescribed for twice daily application to the affected areas. New hair growth was noted in both the children. Both of them are under follow-up for past three months showing progressive growth of hair in the affected areas.

Figure 1

(a) Multiple circular patches of alopecia areata in the girl; (b) Reticulate pattern of alopecia areata in the boy

DISCUSSION

AA is an autoimmune disease which often gets triggered by certain environmental factors in genetically predisposed individuals. The loss of hair in AA is thought to be due to collapse of the normal immune privilege of anagen hair bulb and subsequent attack by CD4+ and CD8+ T lymphocytes.[12] This is responsible for the lymphocytic infiltrate seen around the anagen hair bulbs in histopathological specimens. The immune-mediated attack can also involve follicular keratinocytes, melanocytes, or dermal papillae.[2]

Till date, there are only very few reports of concomitant presentation of AA in siblings in the literature. Concordance rate of 55% was reported among monozygotic twins for AA, whereas such an association is not seen among dizygotic twins or siblings.[3] This high concordance among identical twins is by virtue of sharing the same HLA types. The strong HLA links, especially with Class II alleles, DRB1-1104 and DQB1-0301, suggest the importance of hereditary factors in AA.[1] The inheritance pattern of AA seems to be multifactorial rather than pure Mendelian type. Several studies have suggested that the gene loci for AA are possibly on 2, 6, 10, 14, 16, 18, and 21 chromosomes.[4] The significant association to Down syndrome is linked to the presence of AA gene locus in chromosome 21. Direct association of malnutrition and AA is not reported yet even though malnutrition can produce hair changes like diffuse alopecia, hypopigmentation, thinning, and brittleness of hair. The probable triggering factors for this rare presentation in the siblings may be the stress involved in adjusting with the new environment as well as the social and financial reasons responsible for malnutrition.

The major differential diagnoses for our cases include non-inflammatory Tinea capitis, trichotillomania, and telogen effluvium. Tinea capitis is associated with severe itching and scaling of the scalp along with positive fungal elements in potassium hydroxide mount of scalp scrapings. Trichotillomania has localized short hairs of uneven length with perifollicular erythema following compulsive or habitual pulling by an emotionally disturbed child. Telogen effluvium has a history of major physical or psychological stress which leads to significant shift to telogen phase leading to diffuse hair loss. In contrast to all these, scalp in AA is soft, smooth, and non-pruritic. The different morphological patterns of AA of the scalp are patchy, reticulate, diffuse, ophiasis, ophiasis inversa (sisapho) and totalis.[125] Among these, the diffuse variety and the reticulate pattern need histopathological confirmation to rule out telogen effluvium and malnutrition induced diffuse alopecia. The bad prognostic features include early onset, recurrent episodes, extensive nail involvement, ophiasis pattern, and association with atopy, Down syndrome, and autoimmune diseases.[25] The “Ophiasis” pattern extends from the hair margin into the scalp which is more commonly seen in children.[2] Among children, AA seems to be more common in primary school children, the eldest child, and children who are under psychological stress.[6] The association of stress and psychiatric symptoms in children with AA is a subject of debate.[67] However, it seems advisable to subject the affected children to psychiatric evaluation by an expert. Routine thyroid screening is also recommended for all children with long-standing AA as the incidence of autoimmune thyroiditis is found to be higher among them.[8]

Most of the affected children require only reassurance as spontaneous remission occurs in majority of cases. Treatment options are topical, intralesional, and systemic corticosteroids according to the severity and chronicity of the disease, topical immunomodulators, and topical irritants like dithranol, topical immunotherapy, PUVA therapy, and minoxidil. Even though the topical immunotherapy and intralesional steroids carry better outcome, it is not routinely used in children.[9] Clinicians favor the use of steroids or topical immunomodulators like Tacrolimus for children. Care should be taken to try a particular treatment for at least 3 to 6 months before declaring it as ineffective.[5] The article is presented for the rarity of concomitant presentation of AA in siblings. The role of environmental factors in precipitating a concomitant attack in both the siblings is highlighted along with the special features of AA in children.