Poikiloderma with neutropenia (PN) is a rare autosomal recessive disorder characterized by poikiloderma, chronic noncyclic neutropenia, and recurrent infections. It typically manifests in early childhood, with most cases diagnosed before age 2 years. Poikilodermatous changes supersede an eczematous eruption that occurs in the first year of life. Chronic recurrent infections usually affect the respiratory tract, middle ear, and skin. Dental abscesses also occur. Other variable features include hypogonadotropic hypogonadism, decreased bone density, palmoplantar hyperkeratosis, calcinosis cutis, skin ulcers, midfacial hypoplasia, and dental abnormalities (delayed eruption of teeth, predisposition to gingivitis, and dental caries).

PN is caused by loss-of-function mutations in the USB1 gene located on chromosome 16q21. USB1 is crucial for neutrophil maturation, as well as being expressed in skin keratinocytes. This genetic defect results in impaired neutrophil function, leading to chronic neutropenia and increased susceptibility to infections. Abnormalities in skin cell turnover and repair mechanisms may contribute to the development of skin ulceration.

Without appropriate management, the condition can lead to significant complications, such as bronchiectasis and chronic lung disease, over time. Additionally, the syndrome carries with it an increased risk for myelodysplastic syndrome, acute myelogenous leukemia, and squamous cell carcinoma.

Immunocompromised Patient Considerations: PN patients are inherently immunocompromised due to chronic neutropenia. They require vigilant monitoring for infections, prompt antibiotic treatment, and potentially prophylactic antibiotics to prevent severe infections. Vaccination and avoiding exposure to infectious agents are critical components of care.