Current RMA Instruments
| Reasonable Hypothesis SOP | 69 of 2021 |
| Balance of Probabilities SOP | 70 of 2021 |
Changes from previous Instruments
ICD Coding
- ICD-9-CM Codes: 277.1
- ICD-10-AM Codes: E80.1
Brief description
This is predominantly a skin ("cutanea") disease, caused by a deficiency of a liver enzyme involved in the metabolism of porphyrin. This leads to an excess of porphyrins in the blood ("porphyria"). The term ‘tarda’ refers to the typically late onset of the condition. Porphyrins are photosensitising when transported to the skin and cause skin damage on exposure to light. The condition can be familial (hereditary) or acquired.
Confirming the diagnosis
This diagnosis is based on the clinical presentation, laboratory screening for total porphyrin levels in either plasma or urine, and then specific testing, including porphyrin fractionation, if the screening test is positive.
The relevant medical specialist is a dermatologist.
Additional diagnoses covered by SOP
- chemical, symptomatic, or toxic porphyria
Conditions excluded from SOP
- Erythropoietic protoporphyria#
- Hepatoerythropoietic porphyria#
- Hereditary coproporphyria#
- X-linked protoporphyria#
- other porphyrias#
# non-SOP condition
Clinical onset
Porphyria cutanea tarda (PCT) is generally a disease of adults. It usually presents in mid or later life. The usual major manifesation is chronic blistering of the skin. Other manifestations include skin fragility, scarring, and hyper- and hypopigmentation affecting sun-exposed areas. Liver involvement/damage is also common.
Clinical worsening
PCT is a readily treatable condition with a good prognosis. Relapses may occur following successful treatment. Phlebotomy (drawing blood) and hydroxychloroquine therapy and the main forms of treatment.