Correspondence

Hydroxyurea for Sickle Cell Anemia

N Engl J Med 2008; 359:98-99July 3, 2008

Article

To the Editor:

In her article on hydroxyurea for the treatment of sickle cell anemia, Platt (March 27 issue)1 states that “the red cells of a normal adult generally contain almost 100% hemoglobin A and those of a person with sickle cell anemia contain almost 100% sickle hemoglobin.” This statement is not entirely accurate. In the normal adult, hemoglobin A constitutes about 97% of the total hemoglobin, hemoglobin A₂ constitutes about 2%, and hemoglobin F constitutes about 1%.2

Harris V.K. Naina, M.B., B.S.
Samar Harris, M.B., B.S.
Mayo Clinic College of Medicine, Rochester, MN 55901
naina.harris@mayo.edu

2 References

1. 1

   Platt OS. Hydroxyurea for the treatment of sickle cell anemia. N Engl J Med 2008;358:1362-1369
   Full Text | Web of Science | Medline

2. 2

   Schecter AN, Ajioka RS, Kushner JP. Hemoglobin and heme biosynthesis. In: Young NS, Gerson SL, High KA, eds. Clinical hematology. Philadelphia: Elsevier, 2006:16-33.
   

To the Editor:

Platt highlights the use of hydroxyurea in patients with sickle cell anemia who experience vaso-occlusive crises or acute chest syndrome. She notes that “a large number of eligible patients do not have access to this therapy.” Besides limited access to care, this situation could be related to the potentially serious adverse reactions to hydroxyurea, including reproductive side effects, myelosuppression, and the risk of cancer. However, it appears that compliance with treatment is frequently suboptimal because of the aesthetic consequences of the neglected “minor” cutaneous side effects. These side effects consist mainly of cutaneous hyperpigmentation, alopecia, xerosis, nail pigmentation (longitudinal bands), and leg ulcers.1,2 Therefore, to optimize adherence, it is important to systematically inform patients of these reversible adverse effects before initiating treatment with hydroxyurea.

Claude Bachmeyer, M.D.
Sélim Aractingi, M.D., Ph.D.
François Lionnet, M.D.
Tenon Hospital, 75020 Paris, France
claude.bachmeyer@tnn.aphp.fr

2 References

1. 1

   Zargari O, Kimyai-Asadi A, Jafroodi M. Cutaneous adverse reactions to hydroxyurea in patients with intermediate thalassemia. Pediatr Dermatol 2004;21:633-635
   CrossRef | Web of Science | Medline

2. 2

   Chaine B, Neonato MG, Girot R, Aractingi S. Cutaneous adverse reactions to hydroxyurea in patients with sickle cell disease. Arch Dermatol 2001;137:467-470
   Web of Science | Medline

Author/Editor Response

Naina and Harris correctly point out that given the typical amounts of hemoglobins A₂ and F in the adult erythrocyte, it is more precise to describe the amount of hemoglobin A as approximately 97% rather than “generally . . . almost 100%.”

Bachmeyer and colleagues appropriately note the possible adverse effects of hydroxyurea therapy on the skin and consider the potential for those effects to reduce adherence to treatment. As reported in an article that they cite1 and in other series,2-4 potential adverse effects are of particular concern, since hydroxyurea may exacerbate or precipitate leg ulcers, a condition that is also part of the clinical spectrum of sickle cell anemia.

Orah S. Platt, M.D.
Children's Hospital Boston, Boston, MA 02115
orah.platt@childrens.harvard.edu

4 References

1. 1

   Chaine B, Neonato MG, Girot R, Aractingi S. Cutaneous adverse reactions to hydroxyurea in patients with sickle cell disease. Arch Dermatol 2001;137:467-470
   Web of Science | Medline

2. 2

   Kersgard C, Osswald MB. Hydroxyurea and sickle cell leg ulcers. Am J Hematol 2001;68:215-216
   CrossRef | Web of Science | Medline

3. 3

   Loukopoulos D, Voskaridou E, Kalotychou V, Schina M, Loutradi A, Theodoropoulos I. Reduction of the clinical severity of sickle cell/beta-thalassemia with hydroxyurea: the experience of a single center in Greece. Blood Cells Mol Dis 2000;26:453-466
   CrossRef | Web of Science | Medline

4. 4

   de Montalembert M, Begue P, Bernaudin F, Thuret I, Bachir D, Micheau M. Preliminary report of a toxicity study of hydroxyurea in sickle cell disease. Arch Dis Child 1999;81:437-439
   CrossRef | Web of Science | Medline

Citing Articles (1)

Citing Articles

1. 1

   Avnish Tripathi, Jeanette M. Jerrell, James R. Stallworth. (2011) Clinical complications in severe pediatric sickle cell disease and the impact of hydroxyurea. Pediatric Blood & Cancer 56:1, 90-94
   CrossRef