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DR11.1-2 | HIV Dermatology — PBL Case

CLINICAL SETTING

You are a final-year medical student on a dermatology posting at a district general hospital in India. The clinical registrar asks your group to see a new patient in the outpatient clinic and present the case for group discussion. The patient is Mr Kiran Rao, a 31-year-old male labourer, referred by the general physician with a complaint of skin problems that have been worsening over 4 months. He was diagnosed with HIV 5 months ago and has not yet been started on antiretroviral therapy.

Trigger 1: The presenting complaint and initial examination

Mr Kiran Rao gives the following history: 4 months ago, he noticed a yellowish, greasy scaling rash appearing on his face — mainly over the sides of his nose and eyebrows — along with a persistent dandruff that was worse than he had ever had. This improved partially with an antifungal shampoo his pharmacist gave him but always returned. 8 weeks ago, he developed intense itching with small pimple-like lesions on his chest and upper arms, worse at night but not confined to it. 3 weeks ago, he noticed painless white patches on the side of his tongue that he could not wipe away despite trying. He has lost 7 kg in 4 months. On examination: BP 110/70, HR 96, Temp 37.4°C. Skin: yellowish greasy scales on nasolabial folds, eyebrows, and scalp; erythematous follicular papules with excoriation marks on the chest and proximal upper limbs; no burrows in finger web spaces. Oral cavity: corrugated white plaques firmly adherent to both lateral borders of the tongue; no erythematous base visible on attempted scraping.

DISCUSSION POINTS

Identify the three separate skin/oral lesions described. For each, state the most likely diagnosis, the causative organism or mechanism, and the typical CD4 count range at which it appears.
Mr Rao has not yet had a CD4 count done today. Based on the skin findings alone, what range would you estimate his CD4 count to be, and why? What does the chronological sequence of his lesions tell you about his immune trajectory?
The oral lesion does not scrape off. What single clinical feature distinguishes oral hairy leukoplakia from oral candidiasis, and what does this difference in scrapability tell you about pathogenesis?
What focused investigations would you order at this visit? Justify each in terms of what it will confirm or rule out.

Click to reveal Trigger 2: New lesions and a worrying finding (discuss previous trigger first!)

Trigger 2: New lesions and a worrying finding

Mr Rao's CD4 count returns at 68 cells/μL. Viral load is 210,000 copies/mL. While waiting for his results, the nurse notices two lesions that were not commented upon in the initial review: a 1.2 cm violaceous, slightly firm nodule on his hard palate (painless), and three small, bright-red friable papules on his right forearm that ooze easily when touched. His registrar tells the group: 'These two lesions are easily confused — they can look very similar clinically. Getting the diagnosis wrong here has major management consequences. I want you to work out how to distinguish them.'

DISCUSSION POINTS

Name the two diagnoses you must consider for (i) the palatal violaceous nodule and (ii) the red friable forearm papules. What is the causative agent of each?
Construct a comparison table (at minimum) or clinical argument distinguishing these two diagnoses. Include: causative agent, histological features, systemic associations, and treatment.
A skin biopsy of the forearm papule shows lobular capillary proliferation, plump endothelial cells, and clusters of neutrophils. What does this tell you, and what additional stain would confirm the diagnosis?
Mr Rao is found to have cervical and inguinal lymphadenopathy. Would this change your differential for the palatal lesion? Explain your reasoning.

Click to reveal Trigger 3: ART initiation and a serious skin reaction (discuss previous trigger first!)

Trigger 3: ART initiation and a serious skin reaction

After stabilising his opportunistic infections, Mr Rao is started on a nevirapine + lamivudine + zidovudine first-line ART regimen by the HIV clinic. He is counselled and tolerates the first week well. On day 16 he attends the emergency department. He has: fever 39.1°C; a widespread maculopapular rash covering his trunk, face and proximal limbs; facial oedema; bilateral soft cervical lymph nodes; and ALT 186 U/L (normal <45). There is no blistering, no mucosal erosions, and no skin pain. Differential white count shows eosinophilia of 14%. The emergency doctor is unsure whether to 'just treat the rash' or stop the ART. The dermatology team is called.

DISCUSSION POINTS

Name the clinical syndrome Mr Rao has developed. Systematically justify your diagnosis using each of the five clinical and laboratory features present in this vignette.
The emergency doctor asks: 'Is this the same as Stevens-Johnson syndrome?' Compare and contrast this syndrome with SJS/TEN — use the BSA thresholds for SJS (<10%), SJS-TEN overlap (10–30%), and TEN (>30%), and identify the distinguishing features that are present or absent in this case.
What is the immediate management priority? Is this the same for both this syndrome and SJS/TEN, or does management differ?
After the nevirapine is permanently discontinued, the HIV physician wants to switch to an abacavir-containing regimen. What must be done BEFORE prescribing abacavir, and why? Name the specific test and the consequence it prevents.

Click to reveal Trigger 4: Recovery and a paradoxical worsening (discuss previous trigger first!)

Trigger 4: Recovery and a paradoxical worsening

Mr Rao recovers from the drug reaction. He is switched to a tenofovir + lamivudine + efavirenz regimen. His viral load after 4 weeks is 320 copies/mL (falling) and his CD4 has risen to 145 cells/μL. However, he attends the clinic 5 weeks after ART initiation reporting that his Kaposi sarcoma (diagnosed from the palatal biopsy) lesions are larger, more prominent, and two new ones have appeared on his ankle — despite the fact that he is adhering to ART and his immune parameters are improving. The registrar asks the group: 'Why is he getting worse despite getting better immunologically?'

DISCUSSION POINTS

Explain the mechanism underlying the paradoxical worsening of Kaposi sarcoma after ART initiation. What is this phenomenon called, and what are the diagnostic criteria that distinguish it from ART failure?
Should ART be continued, modified, or stopped? Justify your answer with reference to the viral load and CD4 trajectory.
Reflecting on the full case: identify the three general management principles for HIV-associated dermatoses that have been illustrated across Mr Rao's four clinical encounters. For each principle, cite the specific clinical example from this case.
As a group, identify ONE factual claim you made in this discussion that you are uncertain about. State what you would do to verify it before your next session.