Thyrotoxic periodic paralysis (TPP) is a condition featuring attacks of muscle weakness in the presence of hyperthyroidism (overactivity of the thyroid gland). Hypokalemia (a decreased potassium level in the blood) is usually present during attacks. The condition may be life-threatening if weakness of the breathing muscles leads to respiratory failure, or if the low potassium levels lead to cardiac arrhythmias (irregularities in the heart rate). If untreated, it is typically recurrent in nature.The condition has been linked with genetic mutations in genes that code for certain ion channels that transport electrolytes (sodium and potassium) across cell membranes. The main ones are the L-type calcium channel α1-subunit and potassium inward rectifier 2.6; it is therefore classified as a channelopathy. The abnormality in the channel is thought to lead to shifts of potassium into cells, under conditions of high thyroxine (thyroid hormone) levels, usually with an additional precipitant. Treatment of the hypokalemia, followed by correction of the hyperthyroidism, leads to complete resolution of the attacks. It occurs predominantly in males of Chinese, Japanese, Vietnamese, Filipino, and Korean descent. TPP is one of several conditions that can cause periodic paralysis. Signs and symptoms
An attack often begins with muscle pain, cramping, and stiffness. This is followed by weakness or paralysis that tends to develop rapidly, usually in late evening or the early hours of the morning. The weakness is usually symmetrical; the limb muscles closer to the trunk (proximal) are predominantly affected, and weakness tends to start in the legs and spread to the arms.
Keratolysis exfoliativa (also known as "lamellar dyshidrosis", "recurrent focal palmar peeling", "recurrent palmar peeling": 212 ) is a sometimes harmless, sometimes painful skin condition that can affect the focal surface of the fingers and/or the palm or soles of the feet. It is often misdiagnosed as chronic contact dermatitis or psoriasis. It is characterized by dry skin and superficial, air-filled blisters. These blisters can be peeled off very easily and will leave reddish, tender areas. The loss of this corneal layer of the skin, which protects the underlying layers, leaves the skin more vulnerable to dryness and cracking. Causes
Keratolysis exfoliativa normally appears during warm weather. Due to excessive sweating and friction, in for example athletic shoes, the skin can start to exfoliate. Other factors that can cause exfoliation are detergents and solvents. Another very common cause has been reported from salt water fishermen, who often suffer from these symptoms. It is not sure whether it is from the salt water or whether it is from some bacteria from fish. Treatment
Normally, exfoliation is restricted to a particular area and normal skin will replace the exfoliated parts, so no treatment is needed. Since keratolysis exfoliativa is caused by friction, detergents, and solvents, these factors should be avoided. Creams, especially those with silicone and lactic acid are also helpful. In severe cases, photochemotherapy is an option. Prognosis
In most cases exfoliation resolves spontaneously and no lasting damage is seen. However, some patients experience cracking and even bleeding in extreme cases. See also
Acrokeratoelastoidosis of Costa
Peeling skin syndrome
List of cutaneous conditions

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