Source: https://www.dermnetnz.org/topics/cutaneous-toxicity-from-fish-ingestion
Timestamp: 2019-04-25 01:48:30+00:00

Document:
Author: Dr Lydia Chan, Dermatology Registrar, Dermatology Department, Auckland District Health Board, Auckland, New Zealand. DermNet NZ Editor-in-Chief: Adjunct A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. Copy edited by Maria McGivern/Gus Mitchell. September 2017.
What skin signs can be seen as a result of fish ingestion?
Symptoms of hypervitaminosis A (vitamin A toxicity).
A combination of the above can occur in the same patient. It can be difficult to differentiate the cause as symptoms may appear similar.
What causes scombroid fish poisoning?
Scombroid fish poisoning is caused by eating decomposing scombroid fish (eg, kahawai, mackerel, and tuna). Bacteria in the decomposing fish produce various by-products including scombrotoxin, which contains histamine.
What are the clinical features of scombroid fish poisoning?
What are the complications of scombroid fish poisoning?
Scombroid fish poisoning resolves without complications. In severe cases, symptoms may persist for several days.
How is scombroid fish poisoning diagnosed?
Scombroid fish poisoning is usually diagnosed from a clear history of the onset of symptoms within 1 hour of eating a particular fish.
What is the differential diagnosis for scombroid fish poisoning?
The main differential diagnosis for scombroid fish poisoning is type 1 allergic reaction including anaphylaxis.
Scombroid fish poisoning tends to take minutes to induce a reaction. Other reactions due to fish ingestion tend to progress more slowly, over hours, days, or weeks.
What is the treatment for scombroid fish poisoning?
The treatment for scombroid fish poisoning is rapid-acting oral antihistamines, which may resolve the symptoms within minutes.
The decomposing fish responsible for the reaction should be discarded.
What is the outcome of scombroid fish poisoning?
Scombroid fish poisoning rapidly resolves. Patients can eat the same species of fish again, as long as it has been stored in cold conditions to prevent bacterial decomposition.
What causes Vibrio vulnificus infection?
V. vulnificus infection can follow the consumption of contaminated raw seafood (eg, raw oysters). The organism is killed by cooking the fish. This infection may also contaminate open wounds exposed to warm seawater.
What are the clinical features of Vibrio vulnificus infection?
Painful, rapidly spreading haemorrhagic bullae on the trunk and lower limbs causing necrotising fasciitis in multiple sites.
What are the complications of Vibrio vulnificus infection?
Patients with V. vulnificus infection may become very unwell and require hospitalisation. It is often fatal, especially if treatment is delayed beyond 2 or 3 days.
How is Vibrio vulnificus infection diagnosed?
Infection with V. vulnificus can be suspected in unwell patients if they have a history of eating contaminated seafood or have bathed or splashed in seawater.
The bacteria can be isolated from blood, stool, and/or wound cultures using a special medium.
What is the differential diagnosis for Vibrio vulnificus infection?
Infection with other Vibrio species (eg, V. cholera).
What is the treatment for Vibrio vulnificus infection?
V. vulnificus infection is treated with antibiotics (eg, doxycycline or a third-generation cephalosporin).
What is the outcome of Vibrio vulnificus infection?
The outcome of V. vulnificus infection is usually good with prompt treatment. However, the infection may be fatal in up to 50% of patients with pre-existing liver disease and septic shock. It has been recommended that patients with liver disease do not eat raw shellfish.
What are the clinical features of mercury poisoning?
Skin signs may include colour changes in the hands and feet, with associated pain and itch. Hair loss and nail loss has been described. Excessive sweating and inflammation of the gums may also occur.
What are the complications of mercury poisoning?
Complications from mercury poisoning include pain and colour change in the extremities and permanent loss of teeth resulting from gum inflammation. Hair and nail loss may be slow to resolve.
If the mercury poisoning is severe, patients may develop acute renal failure.
How is mercury poisoning diagnosed?
Mercury poisoning can be diagnosed from measuring levels of mercury in the blood.
What is the differential diagnosis for mercury poisoning?
Various psychiatric illnesses, (eg, depression with low mood and poor appetite).
What is the treatment for mercury poisoning?
The treatment of mercury poisoning includes supportive care, such as correcting any fluid and electrolyte imbalances. Chelation with meso 2,3-dimercaptosuccinic acid may be used to prevent methylmercury uptake by erythrocytes (red blood cells) and hepatocytes (liver cells).
It is essential to avoid further exposure to mercury. Avoid eating the fish species mentioned above. Be aware that various herbal and traditional remedies may also contain mercury.
What is the outcome of mercury poisoning?
The signs and symptoms of mercury poisoning gradually disappear once treatment is started, providing there is no further ingestion.
What causes acute vitamin A toxicity?
Vitamin A analogues (oral retinoids, such as isotretinoin and acitretin).
What are the clinical features of acute vitamin A toxicity?
Acute vitamin A toxicity results in redness of the skin, followed by desquamation, dryness, peeling of the lips, and dry eyes. Hair loss and nail thinning or loss may become apparent after some weeks.
Other features of vitamin A toxicity include a headache, abdominal pain, nausea, and vomiting.
What are the complications of vitamin A toxicity?
A severe overdose of vitamin A can lead to death. The intake of high levels of vitamin A or other retinoids during pregnancy has been associated with birth defects.
How is vitamin A toxicity diagnosed?
The diagnosis of vitamin A toxicity is based on the patient’s signs and symptoms, and a history of the ingestion of vitamin A or a retinoid. There is a poor correlation between toxicity and serum retinol levels, as vitamin A is rapidly metabolised to retinoic acid. Blood samples must be stored in the dark before analysis.
What is the differential diagnosis of vitamin A toxicity?
Scombroid fish poisoning (if the onset of symptoms is acute).
What is the treatment for vitamin A toxicity?
The source of the vitamin A toxicity should be avoided, including fish and various supplements, and herbal or traditional remedies containing vitamin A.
Vitamin A will be processed by the body over time. Fluid and electrolyte abnormalities due to vomiting should be corrected.
What is the outcome of vitamin A toxicity?
The outcome of vitamin A toxicity is good. Skin peeling settles over a few weeks as new skin cells are generated.
New Zealand Ministry for Primary Industries. Mercury in fish. January 2016. Available at: www.mpi.govt.nz/food-safety/whats-in-our-food/chemicals-and-food/mercury-in-fish/ (accessed September 2017).

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