Infant anogenital digitate keratoses: A common but often neglected disease

To the editor: Infant anogenital digitate keratoses (IADK) is a relatively common but often neglected disorder during infancy. It is a recently described disease, and improved awareness of it is essential for precise diagnosis and treatment. Here we present a typical case of IADK. A 2-month-old boy presented to the dermatology clinic with asymptomatic perianal spikes for one month. He was born to a healthy mother by standard vaginal delivery. The boy was full-term and otherwise healthy. The family history was unremarkable. According to his mother, there were no potential triggering factors such as diarrhea, pre-existing dermatitis, or the use of irritant cream. Before the dermatology visit, emollients had been applied for several days without resolution. Physical examination showed multiple perianal spikes, which were hyperkeratotic, follicular, and rigid papules scattering on an erythematous background (Figure 1). Other dermatological physical examinations were normal and no other lesions around the body were observed. The microscopic fungal examination was negative. A dermatoscopic examination revealed plugged follicular orifices and vellus hairs on the top of the papules (Figure 2). A clinical diagnosis of IADK was made. The parent was reassured of the benign nature of IADK with spontaneous regression and perfect prognosis. The lesion resolved without treatment after one month and did not recur. IADK was first described by Bar-Ilan et al.1 in 2022 and was thought to be a subtype of digitate keratoses, a heterogeneous group of keratinization disorders. The pathogenesis is unclear. IADK is characterized by 1–2 mm hair follicular, spiked, yellowish-white or pink keratotic papules with or without an erythematous background in the perianal (and genital) area of infants, without any other regions involved. This condition may appear more commonly in male infants and the patients are in good general condition without discomfort. Differential diagnoses of IADK include candidiasis, multiple filiform verrucae, irritant contact dermatitis, and other digitate keratoses, such as multiple-minute digitate hyperkeratosis, lichen spinulosus, and spiny keratoderma. Dermoscopy shows follicular keratotic papules and can aid in the diagnosis of IADK. Histopathology shows a polyp-like structure without parakeratosis, which is nonspecific.1, 2 IADK is a benign, self-limited disorder, which can be diagnosed based on clinical features such as the transient course in infancy, perianal distribution, and follicular characteristics. Skin biopsy is not recommended considering pain, secondary infection, and scarring. The lesions typically resolve spontaneously within weeks to months and no treatment or intervention is required for IADK.1 Topical corticosteroids may be helpful for the underlying erythema. Follow-up and parental reassurance are appropriate strategies.1 This case details a typical patient with IADK, including the clinical features and the self-limited course, and could help improve the awareness of the disease and avoid unnecessary procedures. Written informed consent was obtained from the patient's parents. The authors declare no conflict of interest.