Dear Editor,
Mastocytosis is a group of disorders characterized by the disorderly infiltration of mast cells in various tissues.[1] The cutaneous variants include maculopapular cutaneous mastocytosis, mastocytoma, and diffuse cutaneous mastocytosis (DCM). Bullous mastocytosis (BM) is a rarer form of DCM, predominantly characterized by bullae.[1] Herein, we report a case of a neonate with bullous mastocytosis.
The one-month-old female child was admitted to the skin ward with multiple itchy red raised lesions and blisters on the right hand 10 days after birth, which gradually increased in extent involving upper and lower limbs, trunk, and face over 15–20 days. The redness increased on rubbing the skin. The child developed a few clear fluid-filled tense blisters over these red lesions which ruptured over 2–3 days on scratching, leaving behind raw areas that gradually healed with hyperpigmentation. There was no history of diarrhea, cyanotic spell, or breathlessness. On examination, the child was comfortable and alert. There were multiple round-to-oval plaques with peau d’orange appearance, size ranging from 2 × 1 to 5 × 4 cm distributed predominantly over the scalp, face, trunk, upper and lower limb, including palms and soles. Few of these plaques were surmounted by tense clear fluid-filled bullae [Figure 1a-e]. Darier’s sign could be elicited. There was no involvement of the mucosa or nails. Based on these findings, a provisional diagnosis of bullous mastocytosis was made with other differentials, including infantile bullous pemphigoid. Blood investigations revealed leukocytosis (16,430 cells/mm3) and an absolute eosinophil count of 230 cells/mm3. The serum tryptase level was 71.7 mcg/L. Peripheral smear did not reveal any abnormality, and bone marrow biopsy could not be done. Ultrasound abdomen and chest X-ray were within normal limits.
Figure 1.
(a and b) Multiple erythematous plaques and urticarial wheals over face, trunk, and both upper and lower extremities. Few clear tense bullae are present at face, forearm, and abdomen (c) Multiple plaques with “peau d’orange” appearance and wheals with brown hyperpigmented margin (d and e) Bullae over palms and soles
Histopathological examination revealed a subepidermal split with a monomorphic infiltrate in the papillary dermis composed of mast cells, marked dermal edema, and few eosinophils [Figure 2a and b]. Direct immunofluorescence was negative. Metachromatic granules of mast cells stained positive for toluidine blue [Figure 2c]. As per the recent consensus, a final diagnosis of diffuse cutaneous BM was made [Table 1].[2] The patient was treated on prednisolone 1 mg/kg with gradual monthly tapering and hydroxyzine 2 mg/kg/day. Bullous lesions healed completely and new blisters were reduced; however, complete remission was not achieved.
Figure 2.
(a and b) Papillary dermis showing monomorphic infiltrate composed of mast cells, dermal edema, and few eosinophils (H & E, 40× and H & E, 100x, respectively, (c) Toluidine blue-stained mast cells. (40×)
Table 1.
Updated diagnostic criteria and classification of mast cell disorders[2]
| Variant and subvariant(s) | Abbreviation | Features/criteria |
|---|---|---|
| Maculopapular cutaneous mastocytosis | MPCM | Positive Darier’s sign Typical pigmented skin lesions |
| Urticaria pigmentosa | UP | Positive histology KIT mutation in lesional skin |
| Monomorphic variant | MPCM-m | Monomorphic skin lesions |
| Polymorphic variant | MPCM-p | Polymorphic skin lesions, no signs/criteria of SM |
| Diffuse cutaneous mastocytosis | DCM | Positive Darier’s sign Diffuse involvement of the entire skin Positive histology Criteria for SM not fulfilleda |
| Cutaneous mastocytoma | Positive Darier’s sign, positive histology | |
| Isolated mastocytoma | One single lesion | |
| Multi-localized mastocytomas | Two or three lesions No signs/criteria of SM |
MPCM – Maculopapular cutaneous mastocytosis, UP – Urticaria pigmentosa, MPCM-m – Monomorphic variant of maculopapular cutaneous mastocystsis, MPCM-P – Polymorphic variant of maculopapular cutaneous mastocystosis, DCM – Diffuse cutaneous mastocytosis, SM – Systemic mastocytosis. aIn children, bone marrow studies are only performed when clinical signs and symptoms and/or laboratory findings are indicative of an advanced hematological diseases
Bullous mastocytosis is a variant of DCM that is characterized by diffuse cutaneous mast cell infiltration manifesting as yellow, thickened, fine “’cobblestoning” or “peau d’orange” appearance of skin with bullae formation.[3,4,5] There are two variants of BM: the neonatal form and the delayed-onset form. According to Orkin et al., the neonatal form is associated with an increased risk of extracutaneous involvement.[3] Around 65% of cases occur within the first 15 years of life, out of which 30% of the cases manifest within the first 6 months of age.[5]
The Index case had multiple plaques showing a “’peau d’orange” appearance with tense blisters. The patient responded to prednisolone and antihistamines with decreased daily blister count, and resolution of erythematous plaque. However, the child kept developing a few new bullae (1–2/week) despite systemic steroids, suggesting an indolent course of the disorder. Parents were counseled to avoid triggering factors, such as heat, friction, insect bites, sunlight, narcotics, anticholinergic preparations, aspirin, and other nonsteroidal anti-inflammatory drugs, and local or systemic anesthetics.
The bullous lesions can be observed in the early phase of all subtypes of mastocytosis and are frequently associated with systemic involvement, affecting bones, spleen, liver, and gastrointestinal tract.[6] Our case had no clinical signs and symptoms suggesting systemic involvement. Delayed-onset BM has minimal extracutaneous involvement with a good prognosis. Hence, regular follow-up is needed in such cases.
The pediatricians and dermatologists should be aware of varied forms of CM because of its rarity, possible extracutaneous involvement, and the distinctive management of each individual case.
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 his 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.
References
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