Phototoxicity
Phototoxic drug-induced rash during treatment with rucaparib
Symptoms/signs
60-year-old female patient.
The patient reports the onset of a rash over her neckline, face and limbs, shortly after sun exposure, in summer, 6 months after starting therapy.
Patient photographs
Clinical presentation
Physical examination of the skin reveals erythema on the neckline, face and lower limbs, with a clear boundary around the areas exposed to sunlight. An erythematous-bullous lesion is also observed on her lower lip.
Medical history
In 2012, she was diagnosed with stage IIIC ovarian cancer. The patient is currently being treated with rucaparib, a small oral molecule that inhibits the Poly(ADP-ribose) polymerase-1 (PARP) enzyme.
Differential diagnosis
Drug-induced phototoxic reaction
Drug-induced photoallergic reaction
Photoaggravated dermatitis
Diagnostic tests
The association with sun exposure and involvement clearly limited to sun-exposed areas suggest a drug-induced phototoxic reaction. In this case, the patient did not undergo a skin biopsy for diagnostic purposes. A histological examination would show necrosis of keratinocytes in the epidermis and vasodilation, oedema in the dermis, with scarce inflammatory infiltrate. Finally, photoallergic testing may be considered when cell-mediated immune pathogenesis is suspected.
Description of the disease
Phototoxic drug reactions are often caused by molecules with ring-shaped chemical structures. The clinical presentation looks like sunburn and occurs shortly after exposure in a dose-dependent manner, both concerning the drug and ultraviolet rays. Such reactions are commonly observed in dermatology, while some manifestations of phototoxicity, such as photoonycholysis and pseudoporphyria, are rarely observed.
In addition, photoallergic rashes are usually associated with drugs containing a sulphuric group, are not dose-dependent, and the skin involvement extends beyond the directly exposed areas.
Pharmacological treatment and patient instructions
Given the exclusive skin involvement and its regression upon cessation of sun exposure, this phototoxicity does not pose any contraindications to continuing the ongoing chemotherapy. In the case of photoallergic reactions, however, the risk of chronicity could justify discontinuing the drug.
Topical therapy with betamethasone/fusidic acid cream is recommended in the evening for 15 days on the bullous lesion on the lip.
Dermocosmetic management
LIPIKAR Syndet AP+, an ultra-gentle cleansing cream suitable for sensitive, itch-prone skin, for facial and body cleansing.
CICAPLAST Baume B5+, a repairing and soothing balm that rebalances the skin microbiome.
Follow-up (adjuvant treatment outcomes)
The patient was re-evaluated after one month, showing healing of the bullous lesion on the lower lip and persistence of mild erythema on the face and neckline.
For patients undergoing chronic drug treatment, it is necessary to limit sun exposure in combination with daily use of sunscreen.