Spontaneously Regressing Acral Congenital Leucoderma

Abstract

Vitiligo is traditionally considered as a pigmentary disorder resulting from the complex interplay of immune cells of genetically predisposed individuals and the environment. Reports of congenital vitiligo are rare, and its existence has been disputed. We describe a 16-day-old male baby with acral congenital vitiligo-like leucoderma and partial spontaneous repigmentation by 2 months. The neonate was born to a mother with autoimmune thyroiditis. The presence of congenital vitiligo-like leucoderma arising in an alloimmune context raises the possibility of alloimmune factors in the depigmentation. A mother presented her second born, a 16-day-old male baby, with diffuse depigmentation over right foot, left foot and ankle, and hypopigmented macules, confluent in areas, over anteromedial right ankle, right leg and right thigh (Fig. 1). The macules were present from birth. There was no poliosis. There were no similar complaints in family members. The mother had autoimmune thyroiditis and was on treatment with carbimazole from the fourth month of her pregnancy and propranolol for 2 months during pregnancy. There were no symptoms of thyroid dysfunction in the neonate. The neonate had normal thyroid stimulating hormone, normal free tetraiodothyronine and slightly elevated free triiodothyronine (FT3-5.5 pg/mL; range 2.3–4.2 pg/mL). The mother was euthyroid on treatment. Both the neonate and the mother had elevated anti-thyroid peroxidase (anti-TPO) antibody titres (>1300 U/mL, normal < 60 U/mL). At the second visit, after 2 months, with no treatment, the baby showed partial spontaneous repigmentation (Fig. 2). The baby was then lost to further follow-up. The existence of congenital vitiligo has been controversial. Lerner and Nordlund reported congenital vitiligo in 1978. Subsequent reports of congenital vitiligo were based on history, and the age of presentation ranged from 2 months to 71 years. Male preponderance and a positive family history of vitiligo were common. The diagnosis of congenital vitiligo has often been attributed to misdiagnosed cases of piebaldism. However, the presence of spontaneous repigmentation excludes piebaldism and, thus, makes congenital vitiligo-like leucoderma a separate entity. Neonatal autoimmune disorders are unusual due to the relative tolerance of the foetal immune system. Most neonatal autoimmune disorders result from the passive transfer of maternal antibodies that target fetal antigens. Microchimerism and aberrant apoptosis of foetal cells are other implicated mechanisms. Anti-thyroid peroxisomal antibodies are the most sensitive antibodies for the presence of autoimmune thyroid disease. There is genetic co-localisation between thyroid and vitiligo autoantibodies, and thyroid autoantibodies are present in around 20.8% of vitiligo patients. Acquired leucoderma resembling vitiligo has also been reported in other alloimmune situations such as post-bone marrow transplantation and post-blood transfusion. Autoimmune reactions triggered by chronic graft versus host disease in genetically predisposed individuals and microchimerism-induced allo-autoimmune reaction have been implicated. Thus, in utero allo-autoimmune reactions may be a possible mechanism of leucoderma in our neonate. We believe that congenital vitiligo-like leucoderma is a distinct entity. Neonatal autoimmunity is rare, and it is often attributed to maternal autoimmunity. More research is needed to know the implications of maternal autoimmunity and allo-autoimmune reactions on the fetal melanocyte.