Lichenoid Drug Eruption following Intravenous Application of Orally Formulated Diamorphine, a Semisynthetic Heroin
We report the case of a 40-year-old male intravenous drug abuser who presented to our outpatient clinic with a 2-week history of pruritic skin eruption on his palms and soles. The patient worked part-time as a carpenter and related the appearance of the skin lesions to exposure to a cleaning agent the previous day when he was working barefoot and with ungloved hands. On clinical examination, he presented with multiple, erythematous, flat-topped, lightly scaly, pruritic papules on his palms and soles, with a predilection for the wrists (fig. ). Painless, white, nonremovable streaks (leukokeratosis) were also seen on the mucosa of the cheeks. A rash consisting of small polygonal papules affecting the rest of the body's surface was additionally observed (fig. ).\nThe patient had been an intravenous heroin abuser for many years and had enrolled in an outpatient opiate-based support program. In this context, he was dispensed oral semisynthetic diamorphine (Diaphin®) under supervision. On repeated questioning, he revealed that he had administered the provided synthetic oral heroin intravenously for the last 6 months on a regular basis. He used to dissolve the tablets in water and heat the mixture before injecting it intravenously. He stated that he was additionally using ‘street’ heroin from time to time. Apart from diamorphine and street heroin, he was not taking any other illegal drugs or medication.\nOur clinical differential diagnosis included a contact allergy to a cleaning agent, a sudden aggravation of an underlying atopic dermatitis, palmoplantar psoriasis, and lichen planus. The histopathologic examination of the samples taken from the right sole showed hyperkeratosis and irregular acanthosis with a band-like dermal infiltrate at the dermo-epidermal junction with eosinophilic colloid bodies and melanophages, consistent with a diagnosis of lichen planus (fig. ). A biopsy taken from the patient's back also revealed lichenoid changes showing focal interface dermatitis with lymphocytes at the dermo-epidermal junction and slight vacuolization of keratinocytes (fig. ).\nExtensive blood workup, including screening for HIV, HBV, HCV and syphilis, was within normal limits except for slightly elevated liver transaminases. Total IgE was moderately elevated at 565 kU/l. Urine drug screening was negative except for methadone and opioids.\nA contact allergy to disinfectants, metals and resins was excluded by patch testing. Because of the possible relationship of lichen planus with drugs, Diaphin was discontinued and replaced by orally formulated methadone and morphine. A lymphocyte transformation test to measure drug-specific T cells was performed. Oral Diaphin was not available for testing. The lymphocyte transformation test was thus performed using pure morphine and codeine and was negative. An allergic reaction to Diaphin could not be excluded or confirmed by testing. Nevertheless, in a self-experiment the patient once again administered the oral formulation of diamorphine intravenously and noticed immediate worsening of the skin lesions and swelling of the hands.\nThe patient was treated with topical steroids, phototherapy with narrowband UVB (311 nm) and oral antihistamines. Because of the intense skin involvement, systemic therapy with acitretin (Neotigason®) was initiated. Due to side effects (headache and nausea), the initial daily acitretin dose of 25 mg was reduced to 10 mg per day. All treatments (acitretin, phototherapy and topical steroids) were discontinued by the patient after 2–3 months and replaced by emollients only. The lichenoid skin changes on his body, palms and soles completely resolved within the following 6 months.