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Popper’s Dermatitis: An Unusual Diagnostic Challenge

Volatile nitrites, and especially isobutyl nitrite or “Popper”, are popular drugs of abuse in Europe, mainly in men that have sex with men (MSM). Inhalation is the most common route of consumption, but direct contact with skin or mucosal membranes has been associated with a local adverse event called “Popper’s dermatitis”. To date, just five cases have been reported, most of them on the face, but also on other parts of the body [1, 2]. A 37-year-old man presented with a 3-day history of erythema, erosions and yellowish vesicles on both nostrils, with a burning sensation. He had no past medical history, apart from a latent syphilis. When directly asked about drug consumption, he admitted he had tried “Popper” for the first time three days previously. Physical examination showed an erosive erythematous plaque over both nostrils, covered by orange-yellowish crusts, reminiscent of impetigo. In the central area, over the columella and nasal tip there were some millimetric yellow vesicles (Figure 1). An examination of the nose ruled out further lesions in nasal mucosa or the septum. Sexually transmitted diseases (STD) screening confirmed latent syphilis but was negative for hepatitis B virus (HBV), human immunodeficiency virus (HIV) and hepatitis C virus (HCV). Bacterial and viral cultures (shell-vial technique with MRC5 human embryonic fibroblasts) were taken but both were negative. Based on these findings, “Popper’s dermatitis” was diagnosed and the patient was instructed to apply emollients daily. The lesions had completely resolved at a 3-week follow-up visit. “Popper” is a general term for volatile substances from the nitrites family, usually alkyl nitrites. In its recreational use it is inhaled, leading to rapid vasodilation and sphincter relaxation, and a feeling of euphoria. Given the low perception of risk related to its consumption, it has become the second most popular drug among European MSM (28,4 %), only after cannabis (30,1 %) [3]. Popper’s dermatitis is infrequently reported, probably due to both underdiagnosis and confusion with more common entities such as impetigo, given its characteristic yellow crusts. In fact, this color is not related to bacterial infection but to the xanthoproteic reaction between Popper and aromatic amino acids present in skin. The nitration of benzene rings of aromatic amino acids leads to coagulative damage with persistent yellowish discoloration [2]. Skin reactions are usually a result of the accidental direct contact of nitrites with the skin or mucosal membranes, causing irritation, erosions and ulcers [1], mainly located on the face (nostrils and columella). Cultures for yeasts, bacteria and virus are usually negative. Histological analyses from ulcers have shown full-thickness epidermal necrosis with little inflammatory reaction [1]. Without treatment, the disorder usually resolves without scarring [2]. The etiology of the disorder is unclear, although the most plausible explanation is an irritant contact dermatitis [4]. Some authors have reported positive contact allergy tests with volatile nitrites at 48 and 72 hours [5], while others have shown negative patch testing after 2 % alkyl nitrite dilution in water [1]. However, positive results may be due to Popper’s irritant nature more than hypersensitivity. Its consumption has been associated with a significantly higher risk of HIV infection among MSM [6, 7]. Recreational drug abuse has also been linked to HCV, HBV, gonorrhea, chlamydia, condylomas and other STDs [8]. Thus, screening for STDs should be offered to all patients presenting with Popper’s dermatitis. Also, young adults presenting the characteristic clinical features should be asked about consumption and substance abuse, as these issues may not be investigated in the standard clinical interview. Other systemic complications of Popper inhalation include cardiovascular disease (bradycardia, vasospasm, hypotension) and hematological disorders, especially methemoglobinemia and hemolytic anemia [9]. In fact, testing for glucose-6-phosphate dehydrogenase (G6PDH) deficiency DOI: 10.1111/ddg.14395 Popper’s Dermatitis: An Unusual Diagnostic Challenge Clinical Letter