Table of Content


Winter 2012, Vol. 20 No. 4

Hong Kong J. Dermatol. Venereol. (2012) 20, 195

Dermato-venereological Quiz

Dermato-venereological Quiz

KM Lam 林嘉雯

A 30-year-old gentleman presented with itchy skin rash and facial flushing 30 minutes after dinner in a fast food shop. On physical examination, his conjunctiva was congested, there was diffuse erythema over face and neck and urticarial plaque over anterior chest and abdomen (Figure 1).

Figure 1 Diffuse erythema over face and eck and urticarial plaque over anterior chest and abdomen.


  1. What is the most likely diagnosis?
  2. The detailed food history was obtained from the patient later. He had french onion soup, bread with butter, baked tuna fish with rice and cola. He did not have any history of allergy to these food before. What is the diagnosis now?
  3. What is the causative agent of the condition?
  4. What are the available treatment modalities?

Answers to Dermato-venereological Quiz

  1. The most likely diagnosis is food allergy.
  2. The diagnosis should be scombroid poisoning.
  3. Scombroid fish (dark fleshed; predominantly tuna) and some nonscombroid fish (e.g. Hawaiian dolphin or mahi mahi) are the most common sources. L-Histidine within muscle tissue is decarboxylated to form histamine and similar compounds. The poisoning is also known as "pseudoallergic" fish poisoning.
  4. Administer an antihistamine for symptomatic control. If the patient is severely ill with hypotension and significant bronchospasm, give intravenous fluid and bronchodilator. Corticosteroids are of no proven benefit.


  1. Paul SA, Howard JD, Eric AW. Field guide to wilderness medicine. 2nd ed. Mosby; 2003.