In children and babies, excessive vitamin A intake or issues with Δ6-desaturase enzymes have been correlated with increased risk. Seborrhoeic dermatitis-like eruptions are also associated with vitamin B6 deficiency. Those with immunodeficiency (especially infection with HIV) and with neurological disorders such as Parkinsons disease (for which the condition is an autonomic sign) and stroke are particularly prone to it. Climate
Low humidity and low temperature are responsible for high frequency of seborrheic dermatitis. Fungi
The condition is thought to be due to a local inflammatory response to over-colonization by Malassezia fungi species in sebum-producing skin areas including the scalp, face, chest, back, underarms, and groin. This is based on observations of high counts of Malassezia species in skin affected by seborrhoeic dermatitis and on the effectiveness of antifungals in treating the condition. Such species of Malassezia include M. furfur (formerly Pityrosporum ovale), M. globosa, M. restricta, M. sympodialis, and M. slooffiae. Although Malassezia appears to be the central predisposing factor in seborrhoeic dermatitis, it is thought that other factors are necessary for the presence of Malassezia to result in the pathology characteristic of the condition. This is based on the fact that summer growth of Malassezia in the skin alone does not result in seborrhoeic dermatitis. Besides antifungals, the effectiveness of anti-inflammatory drugs, which reduce inflammation, and antiandrogens, which reduce sebum production, provide further insights into the pathophysiology of seborrhoeic dermatitis. Eunuchs, owing to their low androgen levels and small sebaceous glands, do not develop seborrheic dermatitis.
Gait abnormality is a deviation from normal walking (gait). Watching a patient walk is the most important part of the neurological examination. Normal gait requires that many systems, including strength, sensation and coordination, function in an integrated fashion. Many common problems in the nervous system and musculoskeletal system will show up in the way a person walks. Presentation and causes
Patients with musculoskeletal pain, weakness or limited range of motion often present conditions such as Trendelenburgs sign, limping, myopathic gait and antalgic gait.Patients who have peripheral neuropathy also experience numbness and tingling in their hands and feet. This can cause ambulation impairment, such as trouble climbing stairs or maintaining balance. Gait abnormality is also common in persons with nervous system problems such as cauda equina syndrome, multiple sclerosis, parkinsons disease, alzheimers disease, vitamin B12 deficiency, myasthenia gravis, normal pressure hydrocephalus, and Charcot–Marie–Tooth disease. Research has shown that neurological gait abnormalities are associated with an increased risk of falls in older adults.Orthopedic corrective treatments may also manifest into gait abnormality, such as lower extremity amputation, healed fractures, and arthroplasty (joint replacement). Difficulty in ambulation that results from chemotherapy is generally temporary in nature, though recovery times of six months to a year are common. Likewise, difficulty in walking due to arthritis or joint pains (antalgic gait) sometimes resolves spontaneously once the pain is gone. Hemiplegic persons have circumduction gait, where the affected limb moves through an arc away from the body, and those with cerebral palsy often have scissoring gait.