When would you suspect renal artery stenosis?

1. Young hypertensive patients with no family history (fibromuscular dysplasia should be suspected)
2. New onset of hypertension in a patient older than 55
3. Resistant hypertension requiring multiple antihypertensive drugs
4. Deteriorating blood pressure control in compliant, long standing hypertensive patients, especially in patients old than 60
5. Deterioration in renal function with angiotensin converting enzyme inhibitors
6. "Flash" pulmonary edema
7. >1.5 cm difference in kidney size on ultrasonography

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Do all renal artery stenoses need treatment?

Not all renal artery stenosis require treatment. Renal artery stenosis may not need treatment if a. It is asymptomatic without causing hypertension or impairment of renal function. b. Degree of stenosis is only mild to moderate or without significant gradient c. The affected kidney is not functioning.

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Ultrasound Doppler of kidney is convenient but the result is more operator dependent with limited sensitivity and specificity, and it may be difficult in obese subjects. CT renal angiogram has high sensitivity and specificity but the iodinated contrast may cause renal impairment and may not be the best choice for patients with renal impairment. MR angiogram, on the other hand, has no significant effect on renal function and has a high sensitivity and specificity.

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Percutaneous renal artery angioplasty and stenting is the usually preferred treatment of choice as it is minimally invasive. The success rate is high and patient may be discharged early. With stenting, the restenosis rate is around 10 to 20%. Blood pressure control and renal function may be improved after the procedure.

Picture 1: Renal artery stenosis

Picture 2: After renal angioplasty and stenting

What are the clinical diagnosis and differential diagnoses?

The clinical diagnosis is pityrosporum folliculitis (PF). PF is frequently misdiagnosed as acne vulgaris. Other differential diagnoses include bacterial folliculitis and HIV eosinophilic folliculitis.

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How would you confirm the diagnosis?

PF is usually a clinical diagnosis. Clinically there is chronic, often pruritic monomorphic papulo-pustular eruption with perifollicular erythema. In contrast to acne vulgaris, comedone is not a feature and face is not involved. Response to anti-mycotic therapy supports the clinical diagnosis of PF. Fungal smear, culture and histologic proof may be required.

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What are the provoking factors for this dermatosis?

PF is caused by Malassezia furfur, formerly known as Pityrosporum ovale. It is a skin commensal in over 75% of healthy people. Most of them do not have any signs and symptoms due to this organism. It tends to overgrow in hot, humid and sweaty environments. Risk factors include diabetes mellitus, immune deficiency, use of systemic antibiotic which alters the normal skin flora, use of systemic steroid, oily skin, occlusive clothing, greasy emollients and sunscreen.

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What other skin diseases are caused by the same pathogenic agent?

Malassezia furfur can also cause pityriasis versicolor and seborrhoeic dermatitis.

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What are the treatments?

Treatments include eliminating predisposing factors, use of antifungal shampoo as cleanser and topical antifungal agents. Systemic antifungals such as ketoconazole and itraconazole may be needed. In severe cases, isotretinoin may be considered.

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