1. To detect the prevalence of skin diseases in patients with IEI in Assiut university Children hospital.
2. To describe the pattern of dermatological manifestation among IEI patients present at Assiut University Children hospital.

The immune system is a complex network of cells and organs which cooperate to protect individuals against infectious microorganisms. B- and T- lymphocytes, phagocytic cells, and soluble factors such as complement are some of the major components of the immune system and have specific critical functions in immune defense. When part of the immune system is missing or does not work correctly, immunodeficiency occurs; it may be either congenital (primary) or acquired (secondary). Primary immunodeficiency diseases (PIDs), also known as inborn errors of the immune system (IEI), are a heterogeneous group of inherited disorders caused by genetic mutations that alter the immune system.

Individual IEI are rare, IEIs as a group are not, and they represent a significant health burden. The updated classification of Inborn Errors of Immunity (IEI), encompassing a total of 555 IEIs, and 17 phenocopies due to mutations in 504 different genes. IEIs are currently categorized into 10 categories, with overlapping phenotypes. These categories are Combined immunodeficiencies, Combined immunodeficiencies with syndromic features, Predominantly antibody deficiencies, Diseases of immune dysregulation, Congenital defects of phagocytes, Defects in intrinsic and innate immunity, Autoinflammatory diseases, Complement deficiencies, Bone Marrow Failure, and Phenocopies of inborn errors of immunity.

IEIs present clinically as increased susceptibility to infections, autoimmunity, autoinflammation, allergy, bone marrow failure, and/or malignancy. IEI is to be suspected if there is recurrent or opportunistic infections, organ specific inflammation, autoimmunity, or continuous systemic immune activation and/or benign or malignant, potentially virally induced lymphoproliferation or tumors are seen together, in various combinations.

The skin is an organ of great importance at the immunological level and is commonly affected in IEI. Although infections are the most common cutaneous finding in IEI patients, noninfectious skin diseases are also quite frequent among those patients. These include allergic, inflammatory autoimmune, and malignant manifestations. Also, pigmentary changes, angioedema, urticaria, vasculitis along with nonspecific findings of eczema, erythroderma, granuloma, and ectodermal dysplasia are among the early presenting symptoms in IEI.

Severe combined immunodeficiency (SCID) patients present with severe, recurrent viral and bacterial infections as well as opportunistic infections very early in life (before 6 months of age). IEI is associated with atopy commonly include severe atopic dermatitis as a distinctive characteristic of the disease due to an immune dysregulation that affects skin barrier function.

To the best of our knowledge, data about the cutaneous manifestations of IEI among patients attending Assiut university Children Hospital are lacking. Thus, the goal of this study is to describe the clinical characteristics of the skin manifestations of pediatric patients diagnosed with IEI, this may deepen the knowledge and increase awareness of physicians about alarming cutaneous finding for IEI, aiding in earlier diagnosis and better management of those patient.

Inclusion Criteria:

• • Age of patients below 18 years old.

  • Both sexes.
  • Patients diagnosed with IEI according to the clinical and laboratory criteria outlined by the latest International Union of Immunological Societies (IUIS) classification or equivalent recognized diagnostic guidelines.

Exclusion Criteria:

• Patients older than 18 years Patients not fulfilling the criteria for diagnosis of IEI or still not diagnosed yet.

Age of patients below 18 years old. both sex,at the Allergy, Immunology, and Rheumatology Unit of Assiut University Children's Hospital