Existing hypotheses are based on the fact that only the hands and feet are involved and posit the role of temperature differences, vascular anatomy, differences in the types of cells (rapidly dividing epidermal cells and eccrine glands).In the case of PPE caused by PLD, the following mechanism has been demonstrated: sweat deposits and spreads the drug on the skin surface; then the drug penetrates into the stratum corneum like an external agent; palms and soles have high density of sweat glands, and their stratum corneum is approximately 10 times thicker than the rest of the body, and becomes an efficient long-term reservoir for the penetrating PLD, which was deposited on the skin before. Diagnosis
Painful red swelling of the hands and feet in a patient receiving chemotherapy is usually enough to make the diagnosis. The problem can also arise in patients after bone marrow transplants, as the clinical and histologic features of PPE can be similar to cutaneous manifestations of acute (first three weeks) graft-versus-host disease. It is important to differentiate PPE, which is benign, from the more dangerous graft-versus-host disease. As time progresses, patients with graft-versus-host disease progress to have other body parts affected, while PPE is limited to hands and feet. Serial biopsies every 3 to 5 days can also be helpful in differentiating the two disorders. Prevention
The cooling of hands and feet during chemotherapy may help prevent PPE.
Various emollients (creams) are recommended to keep skin moist. Corticosteroids and pyridoxine have also been used to relieve symptoms. Other studies do not support the conclusion. A number of additional remedies are listed in recent medical literature. Among them henna and 10% uridine ointment which went through clinical trial. Prognosis
Hand-foot invariably recurs with the resumption of chemotherapy. Long-term chemotherapy may also result in reversible palmoplantar keratoderma. Symptoms resolve 1–2 weeks after cessation of chemotherapy (Apisarnthanarax and Duvic 2003). The range is 1-5 wks, so it has recovered by the time the next cycle is due. Healing occurs without scarring unless there has been skin ulceration or necrosis (skin loss/death). With each subsequent cycle of chemotherapy, the reaction will appear more quickly, be more severe and will take longer to heal. History
Hand-foot syndrome was first reported in association with chemotherapy by Zuehlke in 1974. Synonyms for acral erythema (AE) include: hand-foot syndrome, palmar-plantar erythrodysesthesia, peculiar AE, chemotherapy-induced AE,  toxic erythema of the palms and soles, palmar-plantar erythema, and Burgdorfs reaction. Common abbreviations are HFS and PPE. References
Further reading
Farr, Katherina Podlekareva; Safwat, Akmal (2011). "Palmar-Plantar Erythrodysesthesia Associated with Chemotherapy and Its Treatment". Case Reports in Oncology. 4 (1): 229–235. doi:10.1159/000327767. PMC 3085037. PMID 21537373. Hand-Foot Syndrome or Palmar-Plantar Erythrodysesthesia (1 & 2)