Indian Journal of Dermatology
: 2022  |  Volume : 67  |  Issue : 4  |  Page : 428--431

Acute localised exanthematous pustulosis: A rare cause of localised sterile pustules

Vishal Gaurav1, Chander Grover2, Sonal Sharma3,  
1 From the Department of Dermatology and Venereology, All India Institute of Medical Sciences, New Delhi, India
2 Department of Dermatology and STD, University College of Medical Sciences and Guru Teg Bahadur Hospital, Dilshad Garden, Delhi, India
3 Pathology, University College of Medical Sciences and Guru Teg Bahadur Hospital, Dilshad Garden, Delhi, India

Correspondence Address:
Chander Grover
Department of Dermatology and STD, University College of Medical Sciences and Guru Teg Bahadur Hospital, Dilshad Garden, Delhi

How to cite this article:
Gaurav V, Grover C, Sharma S. Acute localised exanthematous pustulosis: A rare cause of localised sterile pustules.Indian J Dermatol 2022;67:428-431

How to cite this URL:
Gaurav V, Grover C, Sharma S. Acute localised exanthematous pustulosis: A rare cause of localised sterile pustules. Indian J Dermatol [serial online] 2022 [cited 2023 Feb 8 ];67:428-431
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Acute localised exanthematous pustulosis (ALEP) is a less recognised, localised variant of acute generalised exanthematous pustulosis (AGEP), which has been reported in both young and elderly individuals (17–72 years). The most commonly implicated drug is amoxicillin-clavulanic acid fixed drug combination (FDC). ALEP presents acutely as grouped, non-follicular, pinhead-sized, sterile pustules on an erythematous background, involving head and neck, though chest, abdomen, back and limbs may also be involved. The lesions generally resolve spontaneously within 7–10 days.[1] Herein, we report a 19-year-old boy who developed ALEP in response to amoxicillin-clavulanic acid FDC with its dermoscopic features, which have not been reported previously to the best of our knowledge.

A young boy presented to us with history of fever along with pustules localised to lateral aspect of right leg for 2 days. A week prior to this, he had developed acute pharyngitis, for which he was prescribed amoxicillin-clavulanic acid FDC, levocetirizine, and paracetamol. Four days following the intake of these drugs, he noticed burning and redness localised to the lateral aspect of right leg, with subsequent appearance of multiple small pin-head sized pus-filled lesions over this area, concurrent with onset of fever (101°F).

On examination, lesions were in different stages of evolution. Active lesions were seen as multiple, small (2–3 mm), discrete, non-follicular pustules overlying an erythematous and oedematous base [Figure 1]. Few resolving lesions showed a collarette of scale [Figure 2]. Polarised dermoscopy [AM7115MZT Dino-lite Edge 3.0 digital microscope] revealed milky-white round globules overlying an erythematous background with dotted and irregular linear vessels at the periphery [Figure 3]. Rest of the mucocutaneous, general physical and systemic examination revealed no other abnormality.{Figure 1}{Figure 2}{Figure 3}

A Tzanck smear preparation from the pustule revealed a field full of neutrophils without any multinucleated giant cells (MNGs). Complete blood count showed leukocytosis (11,600/mm3) with neutrophilia (84%). Bacterial culture from the pus was sterile. Punch biopsy demonstrated epidermal acanthosis and spongiosis, with sub-corneal and intraepidermal pustules in haematoxylin and eosin-stained sections [Figure 4]. Based on the findings, a diagnosis of ALEP was made and the patient was asked to stop amoxicillin-clavulanic acid FDC, prescribed antipyretics (paracetamol 500 mg on SOS basis) and topical steroids (mometasone furoate 0.1% cream). The pustules resolved completely over a week, with mild residual scaling without any sequelae.{Figure 4}

ALEP was first reported by Shuttleworth (1989) as a localised, recurrent pustular eruption over the chin in a 42-year-old woman following administration of amoxicillin.[1] However, Prange et al.[2] diagnosed the first case of ALEP over the face based on the diagnostic criteria for AGEP, including (i) presence of several dozens of small, mostly non-follicular pustules arising on a widespread oedematous erythema at flexural sites, (ii) histopathologic changes of spongiosis and epidermal pustule formation, (iii) fever (>38°C), (iv) blood neutrophil count (>7 × 109/L) and (v) acute evolution with spontaneous resolution of pustules in less than 15 days.[2],[3] The most commonly implicated drugs are antibiotics, especially β-lactams (including amoxicillin, amoxicillin-clavulanic acid FDC, piperacillin-tazobactam, cefoperazone-sulbactam), vancomycin, levofloxacin and trimethoprim-sulfamethoxazole. Others include NSAIDs (diclofenac, ibuprofen, flurbiprofen), allopurinol, finasteride and chemotherapeutic agents (docetaxel and sorafenib).[4] Although 90% of cases are reported in association with drugs, occasionally cases precipitated by viral, bacterial, fungal or parasitic infections are also reported.[5]

Like AGEP, the pathogenesis of ALEP remains incompletely understood. It is widely accepted to be a Type IV hypersensitivity to the inciting agent (drug or infection). CD8+ cytotoxic T cell (TCcell) recruited to the skin after antigen presentation in association with MHC leads to keratinocyte apoptosis, tissue destruction and vesicle formation through perforin-granzyme B and Fas-Fas ligand pathways. Neutrophils are recruited to this site of inflammation under the chemotactic influence of CXCL8 released by epithelial cells and tissue macrophages, transforming the vesicle into a sterile pustule. This process is synergistically aided by TH17 cells by increasing the production of CXCL8 and preventing neutrophil apoptosis. Recently, a link between pustular psoriasis and AGEP has been proposed due to shared genetic predisposition with IL-36 receptor antagonist (IL36RN) mutation, leading to uncontrolled IL-36 signalling with consequent increased production of IL-1β and α, IL-6 and IL-8.[6]

Because ALEP is characterised by localised pustules, it lends itself to multiple differential diagnoses, summarised in [Table 1]. These can usually be differentiated clinically. Dermoscopy can aid the diagnosis by visualisation of milky-white globules with peripheral dotted vessels over a pinkish-red background. The milky-white globules represent the intraepidermal or sub-corneal neutrophilic collections and the peripheral dotted vessels represent dilated dermal vasculature on histopathology. These features are distinctive, enabling dermoscopy to reliably rule out the common differential diagnoses. The condition resolves spontaneously within 7–10 days after withdrawal of the offending drug without any sequelae.{Table 1}

We are reporting this relatively uncommon phenomenon with dermoscopy findings to sensitise physicians and aid its early recognition and appropriate management.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient has given his consent for the images and other clinical information to be reported in the journal. The patient understands that his name and initials will not be published and due efforts will be made to conceal his identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.


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