Doxycycline-induced staining of teeth and malar rash in a child.

A 6-year-old girl had intractable glaucoma secondary to cataract surgery, and required Glaucoma Drainage Device (GDD) implantation. She subsequently had GDD tube exposure, for which the conjunctiva had to be resutured. At time of discharge, oral doxycycline (5 mg/kg/day od) was started for its anti-inflammatory properties to aid conjunctival healing.[123] Three weeks later, she presented with black staining of all her deciduous teeth and a malar rash on face (Figure 1, Panel A). Parents had given the child the dose twice daily which had resulted in this adverse effect. Doxycycline was stopped immediately. Three months later, the teeth stains and skin rash had disappeared (Figure 1, Panel B). Causality analysis done for this adverse event by Naranjo adverse drug reaction probability scale[4] gave a score of 7 suggestive of probable association of adverse event with drug use.

Figure 1

Panel A: Black staining of the teeth after 3 weeks of treatment with doxycycline (solid arrow) and malar rash over the tip of nose and cheeks (block arrow). Panel B: Disappearance of the rash and reversal of teeth staining after 3 months of stopping the drug

Tetracyclines are responsible for teeth staining because of deposition of drug-calcium complexes in dentine and enamel, which darken on sun exposure. Doxycycline because of its weak calcium binding capacity (19%) compared to tetracycline (39.5%) has been found to be safe in children < 8 years for short-term use without the side effects of visible teeth staining.[56]

Doxycycline is a broad-spectrum antibiotic. The Centre for Disease Control (CDC) has recommended its use for treatment of acute and chronic Q fever and tick-borne rickettsial diseases in young children. In recent times, it has been frequently used as a part of the treatment for ocular surface diseases.[2] Its therapeutic value has been attributed to an ability to inhibit matrix metalloproteinase (MMP) activity and both MMP and interleukin (IL)-1 synthesis. In ophthlamic care, it has been used succesfully for conjunctival erosions over drainage devices, post-trabeculectomy bleb leaks,[3] dry eye, inclusion conjunctivitis, and corneal erosions.

This case snippet should serve to alert ophthalmologists who prescribe doxycycline in children. They should ensure that the parent has understood the correct dosage. Fortunately, in our patient, cessation of the drug resulted in a reversal of teeth stains and the disappearance of the malar rash.

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Conflicts of interest

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