Jonathan Gleadle - How to Pass the FRACP Written Examination

Protoporphyria occurs when there is bone marrow overproduction of protoporphyrin. It is typically diagnosed in early childhood, with toddlers develop pain, stinging, oedema, and itching of sun exposed skin often within 10 minutes of being in the sun but can be longer in adults. Total blood porphyrin over five times the upper limit of normal is diagnostic. Urine colour is normal as protoporphyrin is universally excreted into bile. This leads to complications such as gallstones and cholestasis. Treatment with oral beta‐carotene is most effective, but only works in <1/3 of cases. Activated charcoal, and colestipol are also trialled but often ineffective. Avoidance of sunlight is the main treatment for most patients, is associated with vitamin D deficiency in 50% of patients.

Bullous pemphigoid is a subepidermal blistering disorder that most commonly occurs in older adults. The classic skin lesions are urticarial plaques and tense bullae on the trunk and extremities. Intense pruritus is common, and lesions typically do not scar. Cutaneous lichen planus is most commonly expressed as an eruption of shiny, flat, polygonal, violaceous papules. Dermatitis herpetiformis is an autoimmune blistering disease associated with coeliac disease and characterised by intensely itchy polymorphous vesicular lesions located over the extensor surfaces, back, and scalp.

Bissell D, Anderson K, Bonkovsky H. Porphyria. New England Journal of Medicine. 2017;377(9):862–872.

https://www.nejm.org/doi/full/10.1056/NEJMra1608634

8. Answer: C

Rosacea is an inflammatory facial condition of unknown cause associated with high morbidity due to social avoidance, and mood disorder. Rosacea most commonly manifests in middle age, mostly effects women, and can present with flushing and telangiectasia, inflammatory papules and pustules, or a combination of both. Keratitis is commonly seen in rosacea, but is rarely severe enough to be vision threatening. Long‐term sequelae include phymatous changes, most commonly of the nose.

Despite the unclear pathophysiology, several anti‐inflammatory, and vasoactive medications have been shown to significantly improve symptoms associated with the condition. Topical medications blockading alpha‐receptors significantly reduce vascular symptoms – for example brimonidine and oxymetazoline. For inflammatory symptoms, medications such as metronidazole, ivermectin, azelaic acid have shown significant efficacy. For lesions refractory to topical therapy, combination with low‐dose oral doxycycline or tetracycline is indicated, and for cases refractory to this, low‐dose isotretinoin is effective. For inflamed phymatous changes, anti‐inflammatory treatments can be effective, but for more fibrosed lesions, ablative laser therapies can be effective.

van Zuuren E. Rosacea. New England Journal of Medicine. 2017;377(18):1754–1764.

https://www.nejm.org/doi/full/10.1056/NEJMcp1506630?af=R&rss=currentIssue&page=2&sort=newest

9. Answer: B

In developed countries, scabies epidemics occur primarily in nursing homes, prisons and other long‐term care facilities. Transmission of scabies is predominantly through direct skin‐to‐skin contact. Prevalence rates for scabies are higher in sexually active individuals, immunocompromised, and elderly patients. The S scabiei hominis mite that infects humans is female and is large enough (0.3–0.4 mm long) to be seen with the naked eye. Its life cycle occurs completely on the human, but the mite is able to live on bedding, clothes, or other surfaces at room temperature for 2–3 days, while remaining capable of infestation and burrowing.

Patients usually present with pruritus, erythematous papules, and vesicles in webbed spaces of the fingers, wrist, elbows, and scrotum. Burrows are a pathognomonic sign and represent the intraepidermal tunnel created by the moving female mite.

There are three types of scabies:

1 Classic scabies: Typically, 10–15 mites live on the host. After 4 weeks of primary infection and with subsequent infections, a delayed type IV hypersensitivity reaction to the mites and eggs occurs, which causes the classic skin eruption and its associated intense pruritus.

2 Crusted scabies is a distinctive and highly contagious form of the disease. In this variant, hundreds to millions of mites infest the patient, who is usually immunocompromised, elderly, or physically or mentally disabled and impaired. It can be confused with severe dermatitis or psoriasis because widespread, crusted lesions appear with thick, hyperkeratotic scales over the elbows, knees, palms, and soles. Serum IgE and IgG levels are high in patients with crusted scabies, but the immune reaction is not protective. Crusted scabies carries a higher mortality rate than the classic form of the disease, because of the frequency of secondary bacterial infections.

3 Nodular scabies occur in 7–10% of patients with scabies, particularly young children.

The diagnosis of scabies can often be made clinically in patients with a pruritic rash and characteristic linear burrows. The diagnosis is confirmed by light microscopic identification of mites, larvae, ova, or scybala (feces) in skin scrapings, and skin biopsy is not required.

Scabies treatment includes administration of a scabicidal agent such as permethrin, lindane, ivermectin. There is no single agent ranked most effective with respect to cure and control of adverse effects from the scabies infection.

Chandlera DJ. A Review of Scabies: An Infestation More than Skin Deep. Dermatology 2019;235:79–90.

https://www.karger.com/Article/FullText/495290

10. Answer: C

Organ transplant recipients are at a higher risk (up to a 100‐fold higher) for developing skin cancer compared to the general population. Heart and lung transplant patients develop skin cancer more frequently than liver or kidney transplant patients. The common skin cancers after solid organ transplant are squamous cell carcinoma (SCC), basal cell carcinoma (BCC), melanoma, and Merkel cell carcinoma (MCC). This higher risk is due to immunosuppression. Many centres advise transplant patients to check their skin monthly for worrisome lesions and have yearly dermatological review. Patients should practise adequate sun protection measures, including using sunscreen and wearing protective clothing and be aware of the significant UV exposure that can occur in all seasons.

Sunlight consists of two types of harmful rays that reach the earth: UVA and UVB rays. Overexposure to either can lead to skin cancer. In addition to causing skin cancer, UVA rays can cause age spots or solar lentigines, UVB rays are the primary cause of sunburn.

It is recommended to use a broad‐spectrum sunscreen with a Sun Protection Factor (SPF) of at least 30, which blocks 97% of the sun's UVB rays. Broad spectrum sunscreen can protect skin from both harmful UVA rays and the UVB rays. Higher‐number SPFs block slightly more of the sun's UVB rays, but no sunscreen can block 100% of the sun's UVB rays. High‐number SPFs last the same amount of time as low‐number SPFs and high‐number SPF does not allow you to spend additional time outdoors without reapplication. Sunscreens should be reapplied approximately every two hours when outdoors.