Post cellulitis lymphoedema en plaque: A presentation needing recognition

Dear Editor,

We describe a series of cases presenting with persistent oedematous well-defined plaques over the lower limb following episodes of cellulitis. They shared a similar clinical evolution, course, and histopathological features. Such presentations do not match any known clinicopathological entities. We describe the profile of eight such cases.

The observation was made by the authors over the last 5 years. A standard 4 mm punch biopsy, ultrasound venous doppler of the lower limb, and thyroid profile were studied in all. Other investigations were performed if deemed clinically relevant.

There were six males and two females aged 38 to 62 years [Table 1]. In all the cases, the lesions were noticed over the lower limb 15 to 60 days after subsidence of cellulitis episodes. The lesions were located over the shin (3), posterior (2), or lateral aspect of the leg (3). They were well-defined, erythematous to skin coloured, soft to firm in consistency, non-tender with no surface ulceration or discharge [Figures 1a-1c]. There was a peau d’orange-like appearance on the surface of the lesions [Figure 1b]. All patients were treated adequately with antibiotics for their cellulitis. Four of the eight patients were on continuous oral antibiotics and received additional courses of parenteral antibiotics for those lesions without any improvement. Doppler venous Ultrasound, thyroid profile was normal in all the patients.

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Figure 1a:

Well-defined erythematous edematous plaque over the shin, 4 weeks after cellulitis.

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Figure 1b:

Erythematous plaque with Peau d’orange appearance over the shin.

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Figure 1c:

Erythematous skin coloured plaque over the lower leg.

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Histopathology of these patients showed striking similarities. All showed thin epidermis, pale dermal collagen bundles with multiple dilated vascular channels lined by a single layer of flat endothelial cells [Figure 2]. The collagen fibres were pale, loose, with prominent nuclei and architecture, and spaces between them were preserved. These blood vessels didn’t contain a significant number of RBCs. In one case, an additional deep dermal moderate interstitial neutrophilic infiltrate was observed. The alcian blue stain for mucin was negative in all cases. During clinicopathological correlation, possibilities of lymphedema and mucinosis were under consideration until we saw the evolution of patient no. 7 during his hospital course. He had cellulitis and nodular lymphangitis due to Streptococcus sp (culture proven) [Figure 3a]. When the inflammation subsided with treatment by antibiotics (in the next 3-4 weeks), similar oedematous, well-defined plaques appeared over the area of cellulitis and over the lesions of nodular lymphangitis [Figure 3b] over the thigh. This observation made it certain that the lesions were related to the underlying inflammation associated with cellulitis. In our last three patients, we recommended leg elevation and compression stockings. In available follow-up data of five patients, the lesions subsided in next 2-6 months, gradually, spontaneously, or with foot elevation and compression stockings, which were prescribed in three patients.

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Figure 2:

Histopathology of the lesion showed atrophic epidermis, pale dermal collagen throughout the dermis with multiple dilated small vessels lined by single-layer thin endothelial cells (Haematoxylin & eosin, 40x).

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Figure 3a:

Lower limb cellulitis with nodular lymphangitis in a HIV positive patient..

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Figure 3b:

Oedematous Peau d’orange like lesions over the areas of nodular lymphangitis associated with cellulitis.

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Oedematous and infiltrated plaques over the lower limb generate diverse clinical differentials like necrobiosis lipoidica, pretibial myxedema, obesity related lymphedematous mucinosis, or panniculitic conditions like erythema nodosum, induratum, and medium vessel vasculitis.^1-4 Many of them have significant systemic associations. The described lesions have a distinct clinical appearance, different from the above. Inflammatory dermatoses were ruled out in histopathology. Localised mucinosis was the closest differential, but the special stain was not contributory in any of the cases. Dilated blood vessels in our cases seem to be part of the inflammation and associated with dermal oedema, as suggested by pale collagen bundles. In an oedematous lesion, both capillaries and lymphatics can be dilated.

Cellulitis can be associated with persistent limb oedema, which might take more time to subside. Lymphoedema occurs due to the inability of the existing lymphatics to take away the excessive oedematous fluid, and the associated lymphangitis and fibrosis hamper the fluid clearance. But in our cases, the lesions were superficial and well defined, probably due to dermal compared to subcutaneous oedema, more commonly seen with cellulitis [Figure 4]. The appearance of the lesion mimics that of peau d’orange described in lesions of erysipelas, vulval esthiomene, or oedema of the limb following lymph node obstruction. It is difficult to pinpoint why most of the patients with cellulitis have diffuse circumferential oedema, while a few have localised plaque-like lesions. Possibly, involvement of superficial lymphatics in these patients at those localised sites leads to superficial lymphedema. The presentations were very unique and persisted well after the diffuse oedema of the limb subsided. However, identifying such presentations is important to prevent unnecessary use of prolonged antibiotics in those patients. Many of our patients received antibiotics for months. The histopathology was not characteristic of any disease discussed in the differential diagnosis. Later, after multiple observations, the association with cellulitis and the course of the lesions was clearer. Lymphoscintigraphy could have helped in making the diagnosis. Though it can’t visualise the small cutaneous lymphatic channels separately, it can show the features of dermal back flow (DBF) if there is blockage of deeper lymphatics in the late phase.⁵

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Figure 4:

Histopathology showing thinned-out epidermis, dermal oedema, and many thin-walled blood vessels. (Haematoxylin & eosin, 100x).

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Other complications of lymphoedema include recurrent infections, which can further worsen the oedema. Ulceration and persistent discharge are also troublesome to the patients. It can also develop secondary malignancy ⁶

The usual treatment for lymphoedema consists of conservative and definite management. Leg elevation, compression stockings, and prevention of recurrent cellulitis are the priorities. Surgical treatment is rarely done for persistent, severe cases.⁶ Our patients improved either spontaneously or with compression stockings.

We describe a distinct condition presenting with a localised skin coloured, oedematous plaque following cellulitis of the lower limb. The condition is not associated with any underlying venous abnormality and subsides slowly over the next 4-6 months. We coined a new descriptive term, ‘post cellulitis lymphoedema en plaque,’ for the condition.