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ausdoc. com. au 11 APRIL 2025
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SPOT DIAGNOSIS
Professor Dédée Murrell Head of dermatology, St George Hospital, Sydney; professor, faculty of medicine, UNSW Sydney; and honorary professorial fellow, The George Institute for Global Health, Sydney. Co-authors: Justin Vu, a medical student at UNSW Sydney; and Dr Liana Victory, a clinical research fellow at St George Hospital, Sydney.
What’ s behind those eyes?
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A 76-YEAR-old Caucasian woman presents for follow-up for previous skin cancers. Her medical history includes AF, gastro-oesophageal reflux disease, osteoporosis and diverticular disease. She is taking a direct oral anticoagulant, esomeprazole, denosumab, beta blocker, ACEI and digoxin. Her appearance is altered owing to the prominence of her eyes and visible weight loss. On examination, vital signs are unremarkable apart from a regular pulse rate of 110bpm and weight loss of 10kg in 12 months. The thyroid is enlarged. There are thick scaly plaques bilaterally on the anterior shins, with non-pitting oedema. There is bilateral proptosis with no evidence of ophthalmoplegia or pain with eye movement.
While the exact pathogenesis is not well understood, HS is a multifactorial condition. 5
Contributing factors include follicular occlusion, disturbed skin microbiome, pro-inflammatory cytokines, and inflammation leading to rupture of skin follicles. Bacteria do not appear to be causative, and aspirates from unruptured lesions are typically sterile. However, bacterial colonisation and infection can worsen HS lesions. 2
Risk factors include a family history, obesity, insulin resistance, metabolic syndrome and diabetes, smoking, Crohn’ s disease, and other skin disorders, including acne and psoriasis. 5, 6
There is no cure for HS. Management strategies include weight loss, smoking cessation and topical antiseptic treatments. Antibiotics and incision and drainage of acute abscesses may be needed. Immunomodulatory treatments such as oral steroids, azathioprine, methotrexate and the TNF inhibitor adalimumab may be prescribed. 1, 2, 4
Because medical treatments are often inadequate or challenging in the context of a chronic life-impairing condition, people with HS often seek complementary approaches, including lifestyle modification and supplements. Diet is of particular interest to people with HS. 3, 6
The evidence for dietary change is modest, including anecdotes shared on social media, case reports and case series, cross-sectional and cohort studies, and small interventional studies. 3-5 A paucity of high-quality evidence has resulted in the absence of clear guidelines for this condition. 6
Multiple reviews note a range of aggravating and relieving dietary factors( see table 1).
Nutritional ketosis may help because of elimination of trigger foods such as sugar, wheat and brewer’ s yeast, while also decreasing insulin resistance and assisting with maintenance of normal weight. 6, 7 Additionally, ketones are not simply a fuel, but are known to be signalling molecules that reduce oxidative stress and inflammation. 6
Through exploring dietary approaches to IBS, June found her own way to a meat-based wholefood ketogenic diet which unexpectedly helped the HS. Several mechanisms may account for the attenuation of symptoms, including nutritional ketosis, the reduction of aggravating foods, and the inclusion of foods with nutrients known to reduce inflammation, such as zinc, omega 3 fatty acids and vitamin D. 5
Outcome
June’ s blood results are unremarkable. The GP confirms that June’ s symptoms and past history are consistent with HS and encourages her to continue with the dietary pattern that has worked for her.
References on request from kate. kelso @ adg. com. au
Table 1. Summary of aggravating and relieving dietary factors in HS 3-5
Aggravating factors
Relieving factors
Foods and dietary patterns
High-glycaemic-load Western diets Sugar, wheat Brewer’ s yeast Dairy Nightshade vegetables( eg, tomato, eggplant, potato, capsicum)
Mediterranean diet Paleo diet and autoimmune protocols Low-carbohydrate diets, including nutritional ketosis and carnivore diets
Box 1. Hurley staging system
Stage I – Solitary or multiple, isolated abscess formation, without scarring or sinus tracts.
Stage II – Recurrent abscesses, single or multiple widely separated lesions, with sinus tract formation.
Stage III – Diffuse or broad involvement, with multiple interconnected sinus tracts and abscesses.
Likely mechanisms
Chronic inflammation Insulin resistance and impaired insulin signalling Gut dysbiosis Impaired colonic mucosal barrier
Elimination of trigger foods Decreased insulin resistance Weight loss Anti-inflammatory effects and reduced oxidative stress from ketosis Increase in nutrients that reduce inflammation
Figure 1. June’ s left axilla. Similar nodules were present in her right axilla.
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Which is the most likely diagnosis? a Primary hypothyroidism b Congenital proptosis c Graves’ disease d Neuroblastoma
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ANSWER The answer is c. Graves’ disease is an autoimmune disease resulting in autoantibodies that bind to the thyrotropin( TSH) receptor. Excessive activation of this receptor stimulates both thyroid gland growth and thyroid hormone synthesis, resulting in hyperthyroidism and goitre. Cross-talk between the TSH receptor and insulin-like growth factor 1 receptors in Graves’ disease also leads to orbital fibroblast proliferation, resulting in muscle and fat propagation behind the eye and exophthalmos.
Graves’ disease is characterised by the symptomatic triad of goitre, exophthalmos and pretibial myxoedema, which are all present in this patient. Additionally, AF and tachycardia are potential cardiac complications of Graves’ disease.
It is important to note that pretibial myxoedema is an infrequent manifestation in Graves’ disease. The absence of Graves’ dermopathy therefore does not exclude Graves’ disease.
Features of pretibial myxoedema, when present, include bilateral, non-pitting, scaly skin thickening and induration. There may be well-demarcated violaceous to slightly pigmented papules or nodules. The skin is woody, firm, and fibrosed around the nodules. Typically the lesions are asymptomatic but on occasion, pain or pruritus may be present.
The diagnosis of Graves’ disease is confirmed with pathology demonstrating suppressed TSH and presence of TSH receptor antibodies.
Treatment options for Graves’ disease depend on the degree of systemic involvement. Those with overt hyperthyroidism require therapy to reduce thyroid hormone synthesis, which may be achieved using antithyroid drugs( thioamides), radioiodine, or surgery.
Treatment options for active thyroid eye disease, a debilitating, disfiguring and potentially blinding condition, include IV glucocorticoids or teprotumumab. Teprotumumab is a fully human monoclonal antibody that targets insulin-like growth factor 1 receptor, which can improve proptosis. It may also be effective for Graves’ dermopathy. In the absence of orbitopathy, pretibial myxoedema may be managed with high-potency topical steroids, or intralesional steroid therapy.
References on request from kate. kelso @ adg. com. au