Which factor should alert a clinician to use extra caution when applying ultraviolet light to a patient with psoriasis?

Which factor should alert a clinician to use extra caution when applying ultraviolet light to a patient with psoriasis?

• A. Daily tetracycline (Achromycin) use
• B. Arthroplasty with a metal implant
• C. Penicillin allergy
• D. Long-standing calcium supplement use

Answer: (A)

When using ultraviolet light to treat psoriasis, recognize medications that can make the skin react more strongly to light. Tetracyclines are classic photosensitizers: they absorb UV energy and create photochemical reactions in the skin. This can lead to amplified sunburn-like reactions, redness, swelling, blistering, or pigment changes after UV exposure. If a patient is taking tetracycline daily, UV therapy poses a higher risk of these adverse effects, so clinicians must proceed with extra caution—reduce or space out the UV doses, monitor closely, or consider modifying or delaying treatment until the antibiotic is stopped if possible. The other factors in the list don’t significantly increase photosensitivity to UV light, so they don’t require the same level of caution in this context.

When using ultraviolet light to treat psoriasis, recognize medications that can make the skin react more strongly to light. Tetracyclines are classic photosensitizers: they absorb UV energy and create photochemical reactions in the skin. This can lead to amplified sunburn-like reactions, redness, swelling, blistering, or pigment changes after UV exposure. If a patient is taking tetracycline daily, UV therapy poses a higher risk of these adverse effects, so clinicians must proceed with extra caution—reduce or space out the UV doses, monitor closely, or consider modifying or delaying treatment until the antibiotic is stopped if possible.

The other factors in the list don’t significantly increase photosensitivity to UV light, so they don’t require the same level of caution in this context.