Popping during external snapping hip (lateral-extra articular), occurs when the thickened posterior aspect of the ITB or the anterior gluteus maximus rubs over the greater trochanter as the hip is extended. Internal snapping hip (medial-extra articular) is usually described by the patient as a snapping or locking of the hip with an audible snap and occurs when the iliopsoas tendon snaps over underlying bony prominences. Almost half of patients with internal snapping hip also have inter-articular pathology. Intra-articular
The causes of intra-articular snapping hip syndrome seem to be broadly similar to those of the extra-articular type, but often include an underlying mechanical problem in the lower extremity. The pain associated with the internal variety tends to be more intense and therefore more debilitating than with the external variety. Intra-articular snapping hip syndrome is often indicative of injury such as a torn acetabular labrum, ligamentum teres tears, loose bodies, articular cartilage damage, or synovial chondromatosis (cartilage formations in the synovial membrane of the joint). Diagnostic
Ultrasound during hip motion may visualize tendon subluxation and any accompanying bursitis when evaluating for iliopsoas involvement in medial extra-articular cases. MRI can sometimes identify intra-articular causes of snapping hip syndrome. Treatment
This condition is usually curable with appropriate treatment, or sometimes it heals spontaneously. If it is painless, there is little cause for concern.
Sézary disease, or Sézary syndrome, is a type of cutaneous T-cell lymphoma that was first described by Albert Sézary. The affected T cells, known as Sézarys cells or Lutzner cells, have pathological quantities of mucopolysaccharides. Sézary disease is sometimes considered a late stage of mycosis fungoides with lymphadenopathy. Signs and symptoms
Sézary disease and mycosis fungoides are cutaneous T-cell lymphomas having a primary manifestation in the skin. The diseases origin is a peripheral CD4+ T-lymphocyte, although rarer CD8+/CD4- cases have been observed. Epidermotropism (lymphocytes residing in the epidermis)  by neoplastic CD4+ lymphocytes with the formation of Pautriers microabscesses is the hallmark sign of the disease. Although the condition can affect people of all ages, it is commonly diagnosed in adults over age 60. The dominant signs and symptoms of the disease are:

Generalized erythroderma– redness of the skin
Lymphadenopathy – swollen, enlarged lymph nodes
Atypical T cells – malignant lymphocytes known as "Sézary cells" seen in the peripheral blood with typical cerebriform nuclei (brain-shaped, convoluted nuclei)
Hepatosplenomegaly– enlarged liver and spleen
Palmoplantar keratoderma – thickening of the palms of the hands, and soles of the feet

Diagnosis
Those who have Sézary disease often present with skin lesions that do not heal with normal medication. A blood test generally reveals any change in the levels of lymphocytes in the blood, which is often associated with a cutaneous T-cell lymphoma.