As he mentioned towards the end of his passage, one of the differences he states is, “1. Signs are what a doctor sees, symptoms are what a patient experiences.” if i might add that when he means what a doctor “sees” also means what is smelt, felt, tasted(in rare cases of diagnosis), hear, and sees or the 5 senses. This is the difference that he is talking about when differentiating between a sign and a symptom. A simpler way to word this is that it is all observed by perspective. A fever can be felt and seen by a doctor making it a sign but it can also be a symptom do to the fact that the patient also experiences the fever. So you are right, but technically it is not a special case because there are also other symptoms/signs that fall under this category.
Adil, Mushtaq D.; Kaiser, Peerzada; et al. “Effect of Emblica Officinalis (Fruit) Against UVB-Induced Photo-Aging in Human Skin Fibroblasts”; Journal of Ethnopharmacology; October 28, 2010. <http:///pubmed/20688142>
Dang, .; Parekar, .; et al. “Antiinflammatory Activity of Phyllanthus Emblica, Plumbago Zeylanica and Cyperus Rotundus in Acute Models of Inflammation”; Phytotherapy Research; June 2011. <http:///pubmed/21132843>
Datta, Hema Sharma and Paramesh, Rangesh. “Trends in Aging and Skin Care: Ayurvedic Concepts”; Journal of Ayurveda and Integrative Medicine; April 2010. <http:///pubmed/21836797>
Fatima, Nishat; Pingali, Usharani; and Pilli, Raveendranadh. “Evaluation of Phyllanthus Emblica Extract on Cold Pressor Induced Cardiovascular Changes in Healthy Human Subjects”; Pharmacognosy Research; January 2014. <http:///pubmed/24497739>
Tsai, Wen-Hsin; Yang, Chih-Ching; et al. “Therapeutic Potential of Traditional Chinese Medicine on Inflammatory Diseases”; Traditional and Complementary Medicine; July 2013. <http:///pubmed/24716170>
Yang, Baoru and Liu, Pengzhan. “Composition and Biological Activities of Hydrolyzable Tannins of Fruits of Phyllanthus Emblica”; Journal of Agricultural and Food Chemistry; January 2014. <http:///pubmed/24369850>