Imagine a rare skin condition that mimics common rashes, leading doctors on a wild goose chase—and it all starts with something as everyday as disinfectant-soaked laundry. But here's where it gets controversial: could this hidden culprit be unfairly blamed, or is there more to the story in immunocompromised patients? Stick around as we dive into a fascinating case of Granular Parakeratosis in an HIV-positive individual, peeling back layers to reveal insights that might just change how you think about skin care and hygiene.
Introduction
Granular Parakeratosis (GP) is a peculiar skin disorder characterized by red, scaly patches that most often pops up in those moist, hidden folds of the body, like under the arms or in the groin. It's frequently tied to contact with cleaners or detergents that contain benzalkonium chloride, a common ingredient in disinfectants. For context, benzalkonium chloride is a quaternary ammonium compound used in many household products to kill germs, but it can sometimes irritate the skin. Studies suggest GP affects about 0.005% of people, making it quite rare. Typically, it shows up with redness and flaking in intertriginous areas—those warm, sweaty spots where skin rubs against skin, such as the armpits and inner thighs. These symptoms aren't unique, which explains why GP is often mistaken for other issues like intertrigo (a common rash from irritation) or fungal infections such as tinea corporis (ringworm on the body) or tinea cruris (jock itch). Lesions confined to these intimate areas are especially tricky to diagnose correctly. Now, when HIV infection enters the picture, it can worsen or twist many skin problems due to the body's weakened defenses. In this report, we detail a unique case of GP impacting the scrotum, groin, and thighs of a young man living with HIV, compounded by a secondary Candida albicans infection on his thighs that amplified the symptoms. This documentation not only chronicles the disease's progression and recovery but also aims to boost awareness among clinicians, helping them spot GP with Candida complications in HIV contexts more readily.
Case Presentation
A 32-year-old man diagnosed with HIV came to us with a one-month history of itchy, red, scaly spots on his scrotum, groin, and thighs. These had escalated over the last four days into painful pustules and open sores. Standing at 174 cm and weighing 68 kg, he had undergone multiple fungal tests on his scrotum and groin at various clinics, all coming back negative. His routine hygiene involved soaking his flat-angle underwear in "Huoli 28 Disinfectant," which includes benzalkonium chloride, as part of his HIV-related self-care practices. Lab results showed his HIV viral load was undetectable, below 1.0E+2 IU/mL. He was on a regimen of oral lopinavir/ritonavir and zidovudine/lamivudine to manage his condition. Initially thought to be eczema, the symptoms eased a bit with corticosteroids but flared up badly once he stopped them. A skin exam uncovered symmetrically placed dull-red patches, erosions, and pustules across his scrotum, inguinal folds, and thighs (see Figure 1a for an overview, and Figure 1b for a close-up of the right thigh). Histopathology from the thigh lesions showed hyperkeratosis (thickened outer skin layer), granular parakeratosis (abnormal keratin buildup), basophilic keratohyalin granules in the stratum corneum (the skin's top layer), tiny pustules within the cornified layer, and a mild influx of lymphocytes in the dermis (Figure 2a). Dermoscopic view of the thigh displayed a subtle reddish backdrop with evenly spaced dotted and globular blood vessels, plus some scaling (Figure 2b). Fungal tests on the scrotum and groin were negative again, but a direct microscopic exam of the thigh lesion revealed fungal elements, later confirmed as Candida albicans through culture (Figure 2c). He also had low CD4+ lymphocyte counts (320 cells/μL) with a CD4+/CD8+ ratio of 0.58, indicating immune suppression. Key features pointing to GP included his history of benzalkonium chloride exposure, the location in sweaty folds, parchment-like peeling at the edges, the microscopic keratohyalin granules, and the Candida isolation. We ruled out common HIV-related fungal issues like tinea corporis or tinea cruris because multiple mycological tests on the scrotum and groin were negative across several hospitals, and Candida only showed up in the thigh culture during this visit. Interestingly, the medial thigh—where his boxer shorts pressed closest—was hit hardest, likely due to prolonged contact with disinfectant residues. This extended exposure weakened the skin barrier there, and combined with HIV's immunosuppression, it opened the door for the secondary Candida infection. The lesions cleared up entirely after eight days of intravenous compound glycyrrhizin (60 mL daily), paired with stopping the benzalkonium chloride use. We captured the healing journey with daily photos from days 1 to 8 (Figure 3a–h for overviews, and Figure 4a–h for right thigh close-ups), plus a follow-up at day 27 (Figures 3i and 4i). On day 2, after confirming fungus, we tried topical naphthifine and ketoconazole cream, but he reported intense stinging, so we discontinued it.
Figure 1 Clinical Photographs of Bilateral Thighs, Inguinal Regions, and Scrotum Pretreatment. (a) Overview of Thighs, Inguinal Areas and Scrotum in Supine Position; (b) Close-up View of Right Thigh Eruption.
Figure 2 Representative Images of Histopathology, Dermoscopy, and Fungal Culture. (a) The arrows indicate the retention of basophilic granules within the stratum corneum (HE×100); (b) Uniform dotted and globular vessels on dermoscopy; (c) Fungal culture positive for Candida albicans.
Figure 3 Post-treatment Overview of Thighs Inguinal Areas and Scrotum in Supine Position. (a–h) Posttreatment Overview Thighs Inguinal Areas Scrotum Supine Position Days 1–8; (i) Overview Thighs Inguinal Areas Scrotum Supine Position Day 27 Posttreatment.
Figure 4 Posttreatment Close-up Right Thigh. (a–h) Close-up Right Thigh Days 1–8 Treatment Evolution; (i) Close-up Right Thigh Day 27 Posttreatment.
Discussion
GP, originally described by Northcutt and colleagues in 1991 as "axillary granular parakeratosis," is still a mystery in many ways—its exact causes aren't fully pinned down. While exposure to irritants is a leading suspect, with countless reports linking it to benzalkonium chloride in cleaners or laundry products, not everyone who encounters it develops GP. This hints at underlying skin barrier weaknesses playing a role, as faults in the epidermis can pave the way for inflammatory rashes. For example, think of the skin as a fortress; if its walls are compromised, invaders like irritants can breach more easily. Supporting this, a lack of caspase-14—a crucial enzyme for maintaining that barrier—has been linked to higher parakeratosis rates. In HIV patients, a sharp drop in CD4+ T cells shifts the immune response toward Th2, ramping up allergy risks and messing with skin lipids, leading to dryness. Research shows that drugs like indinavir, used in HIV treatment, boost this xerosis (dry skin) by interfering with vitamin A pathways. Lopinavir/ritonavir, in the same class, might do something similar, weakening the skin and setting the stage for GP. So, GP seems to strike those with vulnerable barriers. Beyond benzalkonium chloride, other triggers include things like occlusion from heat, sweat, friction, diapers, or excess weight, plus chemo agents such as pegylated liposomal doxorubicin.
Epidemiologically speaking, GP usually hits around age 37.8, with women making up 69% of cases, though kids and babies aren't spared. Common sidekicks include eczema (6.2%) and obesity (3.9%). It shows as thickened, red patches or plaques, sometimes verrucous (wart-like) in nature. In darker skin, the redness might hide, complicating diagnosis. Itch is the top complaint, but some feel nothing, while a few mention burning. The armpits are ground zero, followed by groin, under the breasts, genital area, and buttocks. Groin spots often get confused with tinea cruris or Hailey-Hailey disease (a genetic blistering disorder). In our case, the thighs were heavily involved, possibly from his underwear habits—highlighting how lifestyle clues can crack the case. GP is mostly bilateral, but one-sided cases exist.
Treatment leans on topicals like exfoliants, steroids, and vitamin D creams. Systemic options include antibiotics like doxycycline or amoxicillin-clavulanate, retinoids such as isotretinoin, antifungals, and even photodynamic therapy. Some clear on their own. And this is the part most people miss: what about when a fungal infection complicates things? In our patient, the Candida on his thighs was a real puzzler—was it the main event or just a side act? Candida is opportunistic, especially in HIV, but we saw it as secondary. We tried antifungals topically, but irritation led to stopping them. Crucially, the spots healed without continuing that treatment, backing up our view that fixing the GP and barrier let the fungus resolve too.
Compared to GP in HIV-negative folks, our patient's profile stood out: (1) He's male, while females dominate in non-HIV cases; (2) Not overweight, unlike many; (3) Had pustules on top of redness and thickening, rarer in others; (4) Thighs were worst-hit, not just the folds; (5) Treatment worked similarly, though. This case is groundbreaking—as far as we know, it's the first GP in HIV/AIDS, with detailed healing logs for GP plus candidiasis. But remember, it's just one report; larger studies are needed for broader lessons.
And here's where it gets controversial: Is benzalkonium chloride the villain everyone's making it out to be, or do underlying factors like immune status amplify the blame? Some might argue exposure is harmless for most, so why single it out? What if lifestyle choices or even medication side effects are the true culprits? We'd love to hear your thoughts—do you think GP is always linked to disinfectants, or could there be hidden triggers? Agree or disagree in the comments below!
Conclusion
To wrap up, GP is a master of disguise, easily confused with other rashes, especially in sensitive areas like the groin, scrotum, or thighs—and HIV throws in extra hurdles. Immunodeficiency ups the odds of opportunistic bugs, and in this scenario, the added Candida made diagnosis even tougher. Most GP cases tie back to benzalkonium chloride, as seen here, and ditching it alongside anti-inflammatory care led to quick recovery, proving avoidance is key.
Abbreviations
GP, Granular Parakeratosis; HIV, Human Immunodeficiency Virus.
Ethics Statement
The patient gave written permission for this report and images to be published. The Ethics Committee at Jiangxi Provincial Dermatology Hospital approved sharing the details.
Consent Statement
The patient consented to publication of the case.
Acknowledgments
The authors contributed equally. Linyan Ye, Xinze Li, and Bei Liao are co-first authors.
Funding
No funding was involved.
Disclosure
No conflicts of interest.
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