Closing the Gap Between HIV Testing Guidelines and Dermatology: A Narrative Review of Missed Opportunities in Indicator Condition-Guided Testing

Abstract

Background/Objectives: Early diagnosis of HIV remains a key objective of global health strategies; however, nearly half of HIV infections in Europe (47.0%) continue to be diagnosed at a late stage. Individuals with undiagnosed HIV infection frequently present initially to dermatology services with inflammatory or pruritic dermatoses. Indicator condition-guided (IC-guided) HIV testing has been reaffirmed by recent guidelines as a central pillar of differentiated testing services, with explicit recommendations to systematically offer testing when defined conditions are present. Methods: This narrative review compares current HIV testing and IC-guided testing recommendations with major dermatology guidelines. Results: This comparison highlights a persistent misalignment. Although certain conditions, such as herpes zoster in younger adults, crusted scabies and selected forms of chronic pruritus, carry clear recommendations to offer HIV testing, most dermatology guidelines for chronic inflammatory dermatoses do not include HIV testing as part of routine assessment. Observational data and implementation studies indicate that integrating IC-guided testing into dermatology pathways can identify previously undiagnosed HIV infections, often in patients without recognised risk factors. Conclusions: Our observations highlight the need to integrate HIV testing recommendations into dermatology clinical guidelines. Aligning these guidelines with IC-guided testing strategies is not only feasible but can also reduce late HIV diagnoses arising from dermatology services.

1. Introduction

Early diagnosis of HIV remains a central objective of global health strategies. However, many opportunities for timely testing continue to be missed in everyday dermatology practice.

The latest data indicate that 40.8 million adults and children worldwide are living with HIV, and 1.3 million people acquired HIV infection in 2024 [1]. Despite a steady decline in new HIV diagnoses since 2010 (−40% globally; −14% in Western and Central Europe and North America), the target of reducing new HIV infections to fewer than 370,000 by 2025 remains far from being reached. HIV prevalence remains particularly elevated in specific key populations, including sex workers (2.7%), gay men and other men who have sex with men (7.6%), people who inject drugs (7.1%), and transgender individuals (8.5%). Within the European Union and European Economic Area (EU/EEA), sex between men continues to be the most common mode of transmission, accounting for 48% of reported diagnoses with a known transmission mode [1,2].

A persistent challenge in the HIV epidemic remains delayed diagnosis, which is consistently associated with avoidable morbidity, mortality, and onward transmission. A recent meta-analysis estimated that 44.0% of cases globally and 47.0% in Europe are late diagnoses [3]. According to the latest annual report on HIV/AIDS, 48% of the 24,164 HIV diagnoses recorded in 2024 in the EU/EEA were late diagnoses, defined by CD4+ T-cell counts < 350 cells/mm³ [2]. The percentage of people diagnosed at a late stage varies across transmission modes and age groups, with the highest rates observed among men infected through heterosexual contact and among older individuals. Therefore, late presenters are often older adults with presumed heterosexual acquisition and a low perceived risk of HIV infection.

Given their low perceived risk, these individuals do not seek HIV testing on their own initiative. In addition, they are less likely to be offered HIV testing by clinicians, even in the presence of clinical indicator conditions (ICs) that should prompt testing. In a German study, 21% of late presenters had previously attended healthcare services with at least one IC without being offered HIV testing [4]. Similar findings were reported in Italy, where nearly 27% had experienced a missed opportunity [5], and in Greece, where 52.3% of the late presenters had at least one IC that had not resulted in HIV testing [6]. A recent meta-analysis further highlighted substantial missed opportunities for HIV testing among individuals undergoing testing for other Sexually Transmitted Infections [STIs] (only about 61% were tested for HIV concurrently) and even among those diagnosed with an STI (only around 35% were tested) [7].

Notably, individuals with undiagnosed HIV infection often present to dermatology clinics because of inflammatory or pruritic skin conditions. HIV-1 induces distinctive immunological alterations in the skin, which consequently lead to dermatological disorders [8]. HIV-1 causes a massive decline in CD4+ T-cells (the hallmark of HIV infection), resulting in a switch from Th1 to Th2 cytokine polarization. HIV also induces a decrease in the number of skin-resident antigen-presenting cells, compromising the function of the skin-associated immune system. In addition, an expansion of CD8+ T-cells has been reported in HIV-infected but clinically normal skin, resulting in low CD4/CD8 ratios. These dysregulated cytokine responses and altered lymphoid populations contribute to exaggerated inflammation and hypersensitivity reactions [9,10]. Because of all these processes, HIV predisposes individuals to a range of inflammatory and neoplastic disorders, alongside opportunistic infections. Indeed, several infectious, inflammatory, and neoplastic skin and mucosal conditions are pathognomonic of HIV/AIDS [11]. These include Kaposi Sarcoma, scalp scabies, nodular scabies, seborrhoeic dermatitis, papular pruritic eruption, eosinophilic folliculitis, tinea infections, herpes zoster, molluscum contagiosum, oropharyngeal candidiasis, Stevens-Johnson syndrome and toxic epidermal necrolysis, genital herpes, planar warts, impetigo, necrotizing ulcerative gingivitis and necrotizing ulcerative periodontitis.

Despite this evidence, previous studies have shown that HIV testing rate in key dermatological ICs is far below the standards set by European and national HIV testing guidelines and that most disease-specific guidelines do not explicitly recommend HIV testing [12,13,14,15]. This narrative review specifically examines how current HIV testing frameworks, including IC-guided testing strategies, align with dermatology guidelines and identifies key gaps and opportunities for integrating IC-guided HIV testing into routine dermatology practice.

2. Current Recommendations on HIV and IC-Guided Testing

Recent global guidance has clearly reaffirmed the role of IC-guided testing as a key pillar of differentiated HIV testing services [16,17,18]. The 2024 WHO consolidated guidelines on differentiated HIV testing services promote the systematic offer of an HIV test when patients present with conditions in which HIV prevalence exceeds a defined threshold. These guidelines explicitly call for the integration of IC-guided testing into routine clinical workflows, extending beyond traditional HIV and STI settings. In Europe, the 2021 IUSTI European guideline on HIV testing in genito-urinary medicine (GUM) settings recommends that clinicians use well-defined ICs to normalise and routinise HIV testing [17]. Furthermore, IC-guided testing implementation studies and EUROtest guidance emphasize embedding IC-guided testing within everyday clinical pathways and quality assurance frameworks [19].

3. Gaps in Dermatology Guidelines

When examining disease-specific dermatology guidelines, a marked conceptual gap becomes evident [20,21,22,23,24]. For a limited number of conditions, such as herpes zoster in younger adults, crusted scabies in sexual health settings and certain forms of chronic pruritus, there are explicit recommendations or strong suggestions to offer HIV testing, consistent with HIV-focused documents. However, for a wide range of chronic inflammatory dermatoses that have been repeatedly described in association with HIV, such as psoriasis (particularly severe or recalcitrant forms), atopic dermatitis, chronic urticaria, prurigo nodularis and, partially, hidradenitis suppurativa, current European and national dermatology guidelines rarely formalise HIV testing as part of routine clinical assessment. Instead, HIV is usually mentioned only as a comorbidity or as one of many possible causes to consider on a case-by-case basis, without clear, practical recommendations for HIV testing [20,21,22,23,24]. This misalignment creates a paradox: while cross-cutting HIV testing guidelines promote IC-guided testing, the disease-specific documents that shape everyday dermatology practice offer limited support for its implementation [16,17,18,20,21,22,23,24]. Because guidelines play a critical role in guiding clinicians in differential diagnosis and helping them recognise early signs of HIV infection, explicit recommendations for HIV testing are essential to assist dermatologists in identifying undiagnosed HIV infections. In this context, clinicians should obtain a sexual history from all patients presenting with recent-onset inflammatory skin diseases, even when such conditions are not classically pathognomonic of HIV/AIDS.

Table 1. Skin and oral HIV-associated conditions with respect to explicit HIV test recommendations.

HIV-Associated Condition	Key Dermatology/STI Guideline(s)	Explicit Recommendation to Offer HIV Test?	Note on HIV Testing in the Guideline
Kaposi Sarcoma	WHO guidelines on the treatment of skin and oral HIV-associated conditions in children and adults [11]	Yes	Classical AIDS-defining condition and key HIV-associated skin tumour in WHO guidance; HIV testing is standard of care and should be offered systematically.
Seborrhoeic dermatitis	WHO guideline on the treatment of skin and oral HIV-associated conditions in children and adults [11]; EUROtest HIV indicator condition guidance [19]	Conditional	Considered HIV-associated dermatosis in WHO guideline and listed among HIV-ICs in IC-guided testing documents; HIV testing should be considered in severe, extensive, recalcitrant or sudden-onset disease.
Papular pruritic eruption	WHO guideline on the treatment of skin and oral HIV-associated conditions in children and adults [11]	Yes	Selected as one of the core HIV-associated skin conditions in WHO guidance; often represents an early manifestation of HIV; HIV testing is recommended and should be systematically offered.
Eosinophilic folliculitis	WHO guideline on the treatment of skin and oral HIV-associated conditions in children and adults [11]	Yes	Recognised HIV-associated inflammatory dermatosis occurring predominantly in people with HIV at lower CD4 counts; HIV testing is recommended when this diagnosis is made.
Tinea infections (extensive/atypical)	WHO guideline on the treatment of skin and oral HIV-associated conditions in children and adults [11]	Conditional	Included among WHO HIV-associated skin conditions; HIV testing should be offered particularly in extensive, atypical or treatment-refractory tinea, consistent with IC-guided testing principles.
Molluscum contagiosum (extensive/atypical)	WHO guideline on the treatment of skin and oral HIV-associated conditions in children and adults [11]	Conditional	Extensive or atypical molluscum contagiosum is highlighted as suggestive of underlying HIV-related immunosuppression; HIV testing should be strongly considered, especially in adults or in high-prevalence settings.
Oropharyngeal candidiasis	WHO guideline on the treatment of skin and oral HIV-associated conditions in children and adults [11]; Guidelines for the Prevention and Treatment of Opportunistic Infections in Adults and Adolescents With HIV [25]	Yes	Classical HIV-IC and common opportunistic infection in advanced HIV; HIV testing should be systematically offered when diagnosed without an obvious alternative explanation.
Stevens-Johnson syndrome/toxic epidermal necrolysis	WHO guideline on the treatment of skin and oral HIV-associated conditions in children and adults [11]	Conditional	Included among WHO HIV-associated skin/oral conditions; SJS/TEN occur more frequently in people with HIV, although usually drug-induced; HIV testing should be considered, particularly in high-prevalence settings or when additional ICs are present.
Genital herpes (severe/recurrent/atypical)	EUROtest HIV indicator condition guidance [19]; 2021 European guideline on HIV testing in GUM settings [17]	Conditional/Yes (in severe, recurrent or atypical cases)	Recurrent, severe or atypical forms treated as HIV-ICs in IC-guided testing documents; HIV testing should be routinely offered in these presentations and whenever an STI is diagnosed in GUM/STI settings.
Planar warts (extensive/recalcitrant)	WHO HIV-associated skin conditions background text on viral warts [11]	Conditional	Extensive, recalcitrant or atypical viral warts are repeatedly reported as HIV-associated; although not a headline WHO condition, HIV testing should be considered as part of IC-guided strategies, especially when lesions are widespread or treatment-resistant.
Impetigo (recurrent/extensive)	WHO guideline on the treatment of skin and oral HIV-associated conditions in children and adults [11]	No (only general IC logic)	Described in reviews of HIV-associated skin infections but not listed as a specific HIV-IC in major guidelines; HIV testing may be considered when impetigo is recurrent, extensive or accompanied by other ICs, yet no explicit guideline recommendation exists.
Necrotizing ulcerative gingivitis	WHO guideline on the treatment of skin and oral HIV-associated conditions in children and adults [11]	Conditional	Considered HIV-associated oral condition in WHO guidance; regarded as HIV-associated oral disease, usually in advanced immunosuppression; HIV testing should be strongly considered and is consistent with IC-guided testing when this diagnosis is made.
Necrotizing ulcerative periodontitis	WHO guideline on the treatment of skin and oral HIV-associated conditions in children and adults [11]	Conditional	Considered HIV-associated oral condition in WHO guidance; HIV testing is advisable, in line with IC-guided HIV testing strategies.

STI, Sexually Transmitted Infection; WHO, World Health Organization; HIV, Human Immunodeficiency Virus; AIDS, Acquired Immune Deficiency Syndrome; IC, Indicator Condition; SJS/TEN, Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis; GUM, Genito-Urinary Medicine.

summarises how skin and oral HIV-associated conditions are addressed with respect to explicit recommendations to offer HIV testing.

Table 2. Dermatological indicator conditions and corresponding disease-specific guidelines with respect to explicit HIV test recommendations.

Dermatological Indicator Condition (IC)	Key Dermatology/STI Guideline(s)	Explicit Recommendation to Offer HIV Test?	Note on HIV Testing in the Guideline
Kaposi Sarcoma	S1 Guidelines for the Kaposi Sarcoma [26]	Yes	All KS patients without known HIV infection should be offered HIV testing at initial KS diagnosis
Herpes zoster in adults < 50–60 years	German S2k herpes zoster guideline [27]	Yes	Recommends HIV serology in herpes zoster in adults < 50–60 years as an HIV indicator condition
Crusted scabies/scabies in STI/GUM	European guideline for the management of scabies [28]	Yes (in STI/GUM settings)	In sexual health clinics, recommends STI screening including HIV testing in sexually active patients with scabies
Chronic pruritus/prurigo	S2k guideline Diagnosis and treatment of chronic pruritus [20]	Conditional	Lists HIV infection among possible causes; suggests HIV serology when history or clinical findings indicate suspected immunodeficiency or IC
Psoriasis (severe/recalcitrant)	EuroGuiDerm systemic psoriasis guideline; national S3 adaptations [21]	No (routine screening)	Baseline work-up includes HBV/HCV, TB and safety labs; HIV testing not included as standard investigation, mentioned only in sections on comorbid HIV
Atopic dermatitis (moderate–severe)	EuroGuiDerm atopic eczema guideline; Italian S3 guideline [22]	No (routine screening)	Routine diagnostic and pre-systemic panels do not include HIV serology; HIV testing suggested only if clinical or epidemiological suspicion
Hidradenitis suppurativa	European S2k HS guideline [23]	Conditional	Notes increased HIV prevalence; recommends HIV screening particularly before systemic immunosuppressive/biologic therapy or in atypical/suspected HS, but not as mandatory test in all patients
Chronic urticaria	EAACI/GA2LEN/EuroGuiDerm/APAAACI urticaria guideline [24]	No	Diagnostic algorithm does not include HIV testing; serology considered only in presence of specific clinical clues

IC, Indicator Condition; HIV, Human Immunodeficiency Virus; STI, Sexually Transmitted Infection; KS, Kaposi Sarcoma; GUM, Genito-Urinary Medicine; HBV, Hepatitis B Virus; HCV, Hepatitis C Virus; TB, Tubercolosis; HS, Hidradenitis suppurativa; EAACI, European Academy of Allergology and Clinical Immunology; GA²LEN, Global Allergy and Asthma European Network; APAAACI, Asia Pacific Association of Allergy, Asthma and Clinical Immunology.

lists other dermatological conditions with respect to explicit recommendations to offer HIV testing in their respective disease-specific guidelines.

4. Structural Issues in Guideline Development

A further structural issue lies in how many disease-specific dermatology guidelines are developed. Guidelines panels are often dominated by organ-specific or treatment-focused experts, with minimal or no representation from dermatovenereologists and HIV specialists [20,21,22,23,24]. In recent updates of major guidelines on psoriasis, atopic eczema, urticaria and hidradenitis suppurativa, a substantial effort has been devoted to positioning biologics and Janus Kinase (JAK) inhibitors, optimising treatment algorithms and defining safety monitoring protocols [20,21,22,23,24]. However, most of these guidelines lack dedicated sections addressing the active offer of HIV testing in severe, atypical or treatment-refractory disease, or prior to initiating potent immunosuppressive therapy, despite evidence of increased HIV prevalence or atypical presentations in these contexts [18,20,21,22,23,24]. This pattern suggests that HIV testing considerations remain marginal in the prioritisation and composition of dermatology guideline panels.

5. Evidence from Dermatology IC-Guided Testing

Observational data and implementation studies of dermatological IC-guided HIV testing suggest that incorporating systematic HIV testing into dermatology pathways can identify previously undiagnosed infections, often in patients without classical risk factors or perceived risk [29,30]. Case series and scoping reviews have shown that psoriasis, hidradenitis suppurativa and papular pruritic eruptions may represent the first manifestation of HIV infection, sometimes after months of unsuccessful standard treatments [31,32]. When the HIV diagnosis is ultimately made, it is not uncommon for infectious disease specialists to report long histories of refractory or atypical dermatoses that had never triggered an HIV test. These findings support the concept that chronic, severe, sudden-onset, or treatment-refractory dermatoses can serve as practical dermatological ICs warranting the offer of HIV testing.

6. Conclusions and Future Directions

This narrative review highlights three key areas for action. First, dermatologists must recognize the existing conceptual gap and advocate for the inclusion of explicit, practical recommendations on HIV testing in dermatology guidelines, particularly in the presence of severe, sudden-onset, atypical, or treatment-refractory dermatoses, as well as prior to initiating systemic immunosuppressive or biologic therapies. Second, guideline development groups for psoriasis, atopic dermatitis, prurigo nodularis, hidradenitis suppurativa and other chronic dermatoses should systematically include dermatovenereologists and HIV or infectious disease specialists, ensuring the addition of concise, operational sections on the active offer of HIV testing aligned with IC-guided strategies and local epidemiology. Third, HIV testing policy documents and global health agencies should move beyond general calls for the integration of IC-guided testing and facilitate its translation into discipline-specific guidelines, audit metrics, and electronic prompts. Future efforts should also define measurable quality indicators, such as the proportion of patients with selected dermatoses who are offered an HIV test, and evaluate the impact of electronic alerts and educational interventions that normalise IC-guided testing in dermatology. Without such alignment between HIV testing policies and dermatological guidelines, IC-guided testing risks remaining largely theoretical, while late HIV diagnoses continue to occur among patients who have been repeatedly seen and treated in dermatology services.