Letters to the Editor

Indian Pediatrics 2002; 39:207-208  

Non-Bullous Ichthyosiform Erythroderma With Rickets

Maintenance of healthy skeleton requires vitamin D, the main source of which is its biosynthesis in the skin. The cutaneous production of vitamin D depends on healthy, intact skin regularly exposed to sunlight. During exposure, ultraviolet-B photons photolyse cutaneous stores of 7-dehydro-cholesterol to previtamin D3 which undergoes thermal isomerisation to form vitamin D3. Epidermal hyperproliferation as occurs in ichthyosis and psoriasis may disturb this synthesis and result in rickets.

Recently, a 4 years old boy with history of dryness and scaling of skin since birth and diagnosed to have congenital non-bullous icthyosiform erythroderma (NBIE), was referred to us because of an abnormal bio-chemical profile. Except for his dermato-logical problem, he was otherwise healthy and the dietary intake was adequate.

Physical examination revealed normal anthropometric measurements (weight 13 kg and height 96 cm). His skin was dry and scaly from scalp to soles. There were no clinical features suggestive of rickets. Systemic examination did not show any abnormality.

Blood biochemistry showed normal levels of aminotransferases, bilirubin, albumin, globulin, urea and creatinine. There was mild elevation of serum phosphorus (5.5 mg/dl), low calcium (8.0 mg/dl) and elevated alkaline phosphatase (31 KAU/dl). Radiograph of the wrist showed cupping and fraying of distal ends of radius and ulna. A diagnosis of rickets was made and child treated with 600,000 units of vitamin D3 and calcium supplements orally. On follow up 2 weeks later, repeat X-ray of the wrist showed changes of healing rickets and normal blood levels of calcium, phosphate and alkaline phosphatase. A diag-nosis of nutritional rickets was made.

Cutaneous hyperproliferative states like ichthyosiform dermatoses are an uncommon cause of rickets in children(1,2). In a series of 41 children with nutritional rickets, only 3 had associated ichthyosis(2). The factors responsible for development of rickets may be: (i) Alterations in epidermal cholesterol metabolism possibly involving vitamin D receptors(3); (ii) Increased keratinocyte proli-feration resulting in poor or no penetration of skin by sunlight(3); (iii) Associated vitamin D dependent rickets(4); and (iv) Limited sun exposure (to prevent sunburn and sunstroke) because NBIE often deteriorates during summer(3).

Children with nutritional rickets usually have low serum phosphorus levels. The mild elevation in this case was possibly due to prior intake of vitamin D3. Biochemical and radiological abnormalities were mild and consistent with the diagnosis of nutritional rickets. All such patients need life-long "rickets prophylaxis" with vitamin D supple-ments (400 IU/day) as dietary intake alone cannot be relied upon(4).

Devidayal,
Lata Kumar,
Meenu Singh,
Advanced Pediatric Center,
Postgraduate Institute of Medical Education and Research,
Chandigarh 160 012, India.

Correspondence to:
Prof. Lata Kumar,
Head, Department of Pediatrics,
Advanced Pediatric Center,
Postgraduate Institute of Medical Education and Research,
Chandigarh 160 012, India.
E-mail: [email protected]

 

1. Scott CI. X-linked ichthyosis vulgaris. Birth Defects Orig Artic Ser 1971; 7: 243-244.

2. el Hag Al, Karrar ZA. Nutritional vitamin D deficiency rickets in Sudanese children. Ann Trop Pediatr 1995; 15: 69-76.

3. Griffiths WAD, Judge MR, Liegh IM. Disorders of keratinization. In: Rook/Wilkinson/Ebling Textbook of Dermatology, 6th edn. Eds. Champion RH, Burton JL, Burns DA, Breathnach SM. Oxford Blackwell Science, 1998; pp 1483-1588.

4. Holm AL, Goldsmith LA. Impetigo herpeti-formis associated with hypocalcemia of congenital rickets. Arch Dermatol 1991; 127: 1587-1588.