Epidemic dropsy: A study of cutaneous manifestations with histopathological correlation

Introduction

Epidemic dropsy is synonymous with Argemone mexicana poisoning, which is characterised by oedema, vascular changes, cardiac insufficiency, renal failure and glaucoma. It is casually related to unintentional ingestion of seeds of Prickly poppy (Arge mexicana) or its products, most commonly by consuming adulterated mustard oil which is a common cooking medium in India. Epidemic dropsy has a world wide occurrence, epidemics have been reported from India, Mauritius, Fiji, South Africa and Madagascar. The active principles responsible for clinical manifestations are believed to be sanguinarine and dihydrosanguinarine which are toxic alkaloids present in A. mexicana. The epidemic dropsy manifests clinically both with systemic and cutaneous manifestations. The cutaneous features include warmth, erythema, tenderness, pigmentation and hair loss. The correlation of dermatological findings in epidemic dropsy with histopathological features based on a follow up for 2 months, is being reported in this communication.

Materials and Methods

In the last incidence of epidemic dropsy in New Delhi in August-September 1998, 19 cases of established epidemic dropsy presented to the Dermatology clinic. A detailed account of history, presenting complaints, clinical manifestations was recorded. Skin biopsy was performed at the time of presentation in all cases, and it was repeated in 4 cases after a period of 8 weeks.

Results

Of the 19 cases inducted in the study, 15 were males and 4 females. All 19 cases presented with bilateral pitting pedal oedema. Two of the 15 males (10.52%) had similar oedema over the scrotum and penis, with involvement of lower abdomen also. All had persistent tachycardia without associated fever. Myalgia was observed in 8 (42.11%) cases. Erythema with bluish hue (erythrocyanosis), which blanched on pressure, was observed in all cases. The erythema started from distal parts of the limbs and progressed proximally. Erythrocyanosis was seen only on legs in 7 (36.84%) cases, on legs and thighs in 12 (63.16%), on forearms in 4 (21.05%) and on forearms and arms in 2 (10.52%) cases. All cases with erythrocyanosis in limbs had involvement of legs and thighs at the same time. Four (21.05%) cases demonstrated erythrocyanosis on abdomen, out of which, in 2 male cases this erythema extended upto umbilicus including genitalia. A distinct line of dermarcation could be visualised separating the involved and uninvolved skin. Local temperature was raised in 8 (42.11%) cases. Four (21.05%) patients complained of local tingling in the extremities. The palms and soles were pale white, in contrast to the erythrocyanosis on dorsum of hands and feets. Two males (10.52%) developed comedones with monomorphic, bilaterally symmetrical distribution on trunk and arms in a short period of 2 to 4 days.

Cases were followed up for a period of 2 months. Oedema persisted in 15 cases, erythrocyanosis however resolved leaving post inflammatory hype rpigmentation. There was no tendernesss of muscles. Two cases, both females, complained of loss of tufts of scalp hairs.

Histopathological examination from the involved skin showed acellular hyaline materials in the walls of dermal blood vessels. Superficial dermis was oedematous and the subcutis showed central vessels with similar deposits, many of these vessels showed microthrombi. Skin biopsy was repeated in 4 cases after one month when clinically erythrocyanosis was reduced considerably but the pitting oedema persisted. Histopathological report showed a few congested capillaries with sparse mononuclear infiltrate and mild oedema in the superficial dermis.

Discussion

From Delhi, 4 major epidemics of epidemic dropsy have been reported in years 1975, 1983, 1994 and the last one in 1998. In addition, the cases have also been reported sporadically from time to time from this capital city of India and the adjoining state like UP. The onset of oedema is the hallmark of epidemic dropsy and witnessed in all our cases, an observation in cnrformity with the earlier studies. The other significant manifestation was persistent tachycardia without fever, which was observed in all our cases, the similar observation reported in another study. The associated cutaneous features like persistent erythrocyanosis which blanches on pressure, was observed in all cases. Local warmth and tingling help in differentiating this condition from other causes of oedema. The oedema persists in majority of cases even up to 2 months however, erythrocyanosis resolves earlier leaving post inflammatory hyperpigmentation. Similarly, the oedema of the superficial dermis persists for few weeks, along with congested capillaries with sparse mononuclear infiltrate. The toxin sanguinarine, an alkaloid, acts on the capillaries causing vasodilatation and increased permeability, resulting in oedema of varying degrees. The probable explanation for the persistent oedema could be persistence of sanguinarine in dermis.

Epidemic dropsy is now making a resurgence due to antisocial practice of food adulteration. The condition may be diagnosed at an early stage from the cardinal signs and symptoms which include pitting oedema, erythrocyanosis and tachycardia without fever. Early identification of the condition is crucial from epidemiological point of view so that preventive measures can be taken promptly to stop the further use of the contaminated mustard oil.