Triangular alopecia  is hair loss that may be congenital but usually appears in childhood as a focal patch of loss that may be complete or leaving fine vellus hairs behind. : 643  Affected individuals are typically entirely healthy. Hair restoration surgery using follicular unit transplantation has been a successful treatment modality for TTA

Presentation
Association with Other Conditions
TTA has been associated with several disorders, such as Phakomatosis pigmentovascularis. And a rare syndrome Setleis syndrome. It is inherited by the autosomal dominant trait and is characterized by cutis aplasia or atrophic skin at the temples, which is said to resemble forceps marks. There may also be a coarse facial appearance, anomalies of the eyelashes and eyebrows, and periorbital puffiness. Frequency
The suggested frequency for this condition in the general population is around 0.11%. The hair loss is non-progressive and does not expand beyond these areas. It is a non-inflammatory, non-scarring form of hair loss easily confused with alopecia areata. In one report, the condition was incorrectly believed by the parents to be induced by doctors inserting intravenous cannulas into scalp vessels during the neonatal period. The condition is permanent and the affected skin does not change later in life.Of the 53 reported cases of TTA, more than half (55.8%) were detected in childhood between the ages of 2 and 9 years, while 36.5% were detected at birth and only 3.8% (only two cases) in adulthood. See also
Alopecia
Skin lesion
List of cutaneous conditions


== References ==
Newborns with a mother who was potentially exposed and who have positive blood tests, microcephaly or intracranial calcifications  should have further testing including a thorough physical investigation for neurologic abnormalities, dysmorphic features, splenomegaly, hepatomegaly, and rash or other skin lesions. Other recommended tests are cranial ultrasound, hearing evaluation, and eye examination. Testing should be done for any abnormalities encountered as well as for other congenital infections such as syphilis, toxoplasmosis, rubella, cytomegalovirus infection, lymphocytic choriomeningitis virus infection, and herpes simplex virus. Some tests should be repeated up to 6 months later as there can be delayed effects, particularly with hearing. Infant feeding in areas of Zika virus transmission
In response to the widespread transmission of Zika virus during the 2016 outbreak and concerns of viral genetic material detected in breast milk the World Health Organization (WHO) released a Guideline of infant feeding in areas of Zika virus transmission, first in 2016 and updated in 2021, where the evidence showed that despite the detection of Zika virus in breast milk, there is unclear evidence of transmission to the infant, and considering that Zika virus infection among infants is mild, the balance between desirable and undesirable effects favours breastfeeding versus not breastfeeding. According to the 2021WHO guidelines:
Infants born to mothers with suspected, probable or confirmed Zika virus infection or who reside in or have travelled to areas of ongoing Zika virus transmission should be fed according to normal infant feeding guidelines.