DR11.1-2 | HIV Dermatology — Glossary

An NRTI that causes a systemic hypersensitivity reaction in carriers of the HLA-B*57:01 allele; the drug must be stopped permanently and never rechallenged once hypersensitivity occurs, as rechallenge can be fatal.

A specific opportunistic infection or malignancy (e.g. Kaposi sarcoma, oesophageal candidiasis) whose presence in an HIV-positive person indicates progression to AIDS.

Combination drug therapy that suppresses HIV replication and restores CD4 counts and immune function; the cornerstone of management that causes most HIV-associated dermatoses to improve.

A bacterial infection caused by Bartonella species producing friable vascular papules and nodules that can mimic Kaposi sarcoma at low CD4 counts; importantly, it is curable with antibiotics.

The genus of bacteria (B. henselae, B. quintana) responsible for bacillary angiomatosis in immunocompromised hosts.

The percentage of the skin surface affected — here, by epidermal detachment — used to classify the SJS/TEN spectrum (SJS <10%, overlap 10–30%, TEN >30%).

The number of CD4+ T-helper lymphocytes per microlitre of blood; the principal laboratory marker of immune status in HIV and the value against which the risk of specific dermatoses and opportunistic infections is gauged.

Drug reaction with eosinophilia and systemic symptoms — a severe reaction with a latency of roughly two to eight weeks, characterised by fever, facial oedema, lymphadenopathy, eosinophilia, and internal organ involvement (especially hepatic).

An NNRTI that can cause a maculopapular rash, typically milder and more often self-limiting than the nevirapine rash; sometimes used as a substitute when nevirapine must be stopped.

An intensely pruritic eruption of follicular papules and pustules on the upper trunk, neck, and face, characteristically associated with moderate-to-advanced HIV immunosuppression.

A human herpesvirus (HHV-4) that, among other associations, causes oral hairy leukoplakia in immunosuppressed individuals.

Reactivation of latent varicella-zoster virus producing a painful vesicular dermatomal eruption; in HIV it is often multidermatomal, severe, or recurrent and may indicate immunosuppression.

A combined immunoassay that detects both HIV p24 antigen and anti-HIV antibodies, shortening the diagnostic window; a reactive result is confirmed per laboratory protocol.

A human leukocyte antigen allele that predicts abacavir hypersensitivity; pre-treatment screening for it, and avoidance of abacavir in carriers, virtually eliminates the immunologically confirmed reaction.

Also called Kaposi sarcoma-associated herpesvirus; the causative agent of Kaposi sarcoma, reactivating to produce neoplasia at low CD4 counts.

A paradoxical inflammatory worsening of existing or subclinical infections occurring within weeks of starting antiretroviral therapy as the recovering immune system reacts; managed by continuing ART, treating the infection, and adding steroids for severe flares.

A vascular neoplasm caused by human herpesvirus-8 (HHV-8), presenting as violaceous macules, plaques, and nodules on skin and mucosa; the most important HIV-associated cutaneous malignancy and an AIDS-defining condition.

A bedside test in which a skin scraping is treated with potassium hydroxide to dissolve keratin and reveal fungal elements — septate hyphae in dermatophytosis, pseudohyphae and budding yeast in candidiasis.

A poxvirus infection producing pearly, umbilicated papules; in HIV the lesions may be numerous, giant, or confluent, especially on the face, reflecting impaired immune control.

A symmetrical, blanching, measles-like eruption of macules and papules; the commonest, usually benign, cutaneous drug reaction, which may settle even if the drug is continued under observation.

Infection by Candida species producing removable white plaques (oral thrush) with an erythematous base, or angular cheilitis; a KOH mount shows pseudohyphae and budding yeast.

An NNRTI that commonly causes an early morbilliform rash and is the ART drug most associated with Stevens-Johnson syndrome, toxic epidermal necrolysis, DRESS, and hepatotoxicity; a 14-day half-dose lead-in reduces rash incidence.

A clinical sign in which lateral pressure on the skin causes the epidermis to shear away; its presence indicates epidermal fragility, as in advancing SJS/TEN.

A class of antiretroviral drugs (e.g. nevirapine, efavirenz) that inhibit HIV reverse transcriptase; the NNRTIs are the most important antiretroviral causes of cutaneous drug reactions.

A class of antiretroviral drugs (e.g. abacavir, zidovudine) that inhibit reverse transcription; abacavir causes pharmacogenomic hypersensitivity and zidovudine causes hyperpigmentation.

An infection caused by an organism that ordinarily does not cause significant disease in an immunocompetent host, but produces serious illness when cell-mediated immunity is impaired, as in advanced HIV.

A white, vertically corrugated ('hairy') plaque on the lateral border of the tongue caused by Epstein-Barr virus (EBV); characteristically cannot be scraped off, distinguishing it from candidal thrush.

A common, intensely itchy, symmetrical papular eruption of the limbs and trunk seen in HIV, frequently with excoriation and post-inflammatory hyperpigmentation; an important marker of HIV in resource-limited settings.

Re-administration of a drug after a previous adverse reaction; contraindicated and potentially fatal after a severe cutaneous adverse reaction or abacavir hypersensitivity.

A chronic inflammatory dermatosis causing greasy, erythematous scaling of sebum-rich areas (scalp, face, central chest); in HIV it is an early, often extensive and refractory, manifestation.

A category of potentially life-threatening drug reactions including SJS, TEN, and DRESS, distinguished from benign rashes by mucosal involvement, blistering, systemic features, and the need for immediate drug withdrawal.

The intermediate band of the SJS/TEN spectrum, defined by epidermal detachment of 10–30% of body surface area.

A severe cutaneous adverse reaction with mucosal involvement and epidermal detachment of less than 10% of body surface area; a dermatological emergency requiring immediate withdrawal of the causative drug.

The most severe form of the SJS/TEN spectrum, with epidermal detachment of more than 30% of body surface area; managed like a major burn with intensive supportive care.

A rapid bedside cytological test in which scrapings from the floor of a fresh vesicle are stained to demonstrate multinucleated giant cells, supporting a diagnosis of herpes simplex or zoster.

An NRTI that characteristically causes benign hyperpigmentation of the nails (longitudinal melanonychia), oral mucosa, and skin through a direct melanocyte effect — not an allergic reaction.