Parthenium dermatitis manifesting clinically as polymorphic light eruption and prurigo nodularis- like lesions with vasculitis-like picture on histopathology

Abstract

Parthenium dermatitis is a widespread and distressing dermatoses in rural and urban India caused by the air borne allergen of the Compositae weed Parthenium hysterophorus. Parthenium dermatitis has been thought to be mediated solely by type IV hypersensitivity, but recently a combined immediate (type I) and delayed (type IV) hypersensitivity mechanism has been postulated in the initiation and perpetuation of parthenium dermatitis, especially in sensitized subjects with an atopic diathesis. Initially, the exposed sites of the body are involved. Later in the course of the disease, unexposed sites may get involved. Various clinical presentations have been described in parthenium dermatitis. Typically, it presents as an air borne contact dermatitis (ABCD) involving the eyelids and nasolabial folds Other presentations include a photodermatitis (essentially a pseudo photodermatitis), atopic dermatitis, seborrheic dermatitis, exfoliative dermatitis, hand dermatitis. Photosensitive lichenoid dermatitis and prurigo nodularis are rarer presentations. Uncommon presentations have been described in parthenium dermatitis. They include prurigo nodularis-like lesions and photosensitive lichenoid eruption. Three cases are presented, two of whom presented as polymorphic-like lesions and one as prurigo nodularis. All three patch tested positive to parthenium on Day 2. Prick testing was positive in two of the three patients. Parthenium dermatitis mimicking polymorphic light eruption has not been reported. Histopathology revealed vasculitis in the lesional skin in two of the patients. Although leukocytoclastic vasculitis has been reported earlier from the prick-tested site, this is the first report demonstrating the presence of vasculitis in lesional skin of parthenium dermatitis.

Parthenium the terminator: An update

“… ABCD [ Figure 4 ] Pseudophotodermatitis [ Figure 5 ] Atopic dermatitis [ Figure 6 ] Seborrheic dermatitis Exfoliative dermatitis Chronic actinic dermatitis[ 21 ] [ Figure 7 ] Photosensitive lichenoid dermatitis Hand dermatitis Prurigo nodularis-like[ 23 24 ] [ Figure 8 ] Polymorphous light eruption (PLE)-like[ 23 ] [ Figure 9 ] Lichen nitidus-like[ 25 ] …”

“…The dermatitis in the depigmented area did not resolve until potent topical corticosteroids and systemic azathioprine were instituted. [ 23 ]…”

“…[ 53 ] Leukocytoclastic vasculitis has been reported from the LPR of the prick tested site in parthenium dermatitis and from the lesional skin of parthenium dermatitis. [ 22 23 54 ] Photoaggravation, heat intolerance and flexural involvement are the features of atopic dermatitis. [ 55 ] Various clinical patterns of parthenium dermatitis such as flexural eczema, prurigo nodularis, chronic actinic dermatitis can be observed in patients with an atopic diathesis.…”

“…[ 54 ] The additional involvement of atopy (type I hypersensitivity) would explain the varied clinical presentation. [ 23 ] The serum IgE is usually elevated in an atopic patient with parthenium dermatitis.…”

How atopic is prurigo in the tropics?: An etiological survey in South India

“…Contact dermatitis to parthenium has been reported to cause prurigo-like nodules. [ 3 ] Hence, this pilot study was planned to assess the role of various known etiopathological factors, especially atopy and parthenium sensitivity in our patients of prurigo nodularis.…”