A baby with photosensitivity and red teeth

A 10-month-old male baby, first issue of a consanguineous marriage, presented with history of intermittent bullous lesions and red-colored urine since the first week of life. The parents stated that the baby used to cry incessantly when exposed to sun and develop blisters, containing both clear fluid and pink/red-colored fluid, on the face, hand and feet, starting from the fifth day of life. These bullae used to rupture in a few days and heal with scarring and irregular pigmentation. The parents also noticed red discoloration of urine and staining of diapers since the seventh day of life. Rest of the history was unremarkable and no other family members were suffering from similar disease. On examination, multiple well-defined atrophic scars were found, distributed over the photoexposed sites (head, face, extensors of upper extremities and feet) [Figure 1]. There was generalized hypertrichosis, which was coarser on the photoexposed areas. The scalp was notable for ulcers and scarring alopecia. Examination of the oral cavity revealed red-stained lower central incisors and gum hypertrophy [Figure 2]. Systemic examination was non-contributory. Wood's lamp examination showed bright red fluorescence in the teeth, urine and blood. Routine investigations including complete blood count were within normal limits. Urine sample was positive for uroporphyrin using the fluorescence method. Histopathology from the bullous lesion showed cleft at the subepidermal level with no inflammation. The dermis was notable for dermal papillae protruding into the blister cavity (festooning). Based on clinical presentation, wood's lamp examination findings, uroporphyrin in urine, erythrodontia (red-stained teeth) and histopathology findings, diagnosis of Congenital erythropoietic porphyria (CEP) was made.

Figure 1.

Multiple well defined atrophic scars on the extensor part of the upper limb. Note hypertrichosis

Figure 2.

Scarring alopecia and crusted ulcers on the scalp. Note red-stained lower central incisors (erythrodontia)

We considered dystrophic epidermolysis bullosa (DEB) as differential diagnosis. Presence of lesions in the photoexposed areas (not only acral and trauma prone parts), photosensitivity, red discoloration of urine, hypertrichosis and wood's lamp findings were in favor of the diagnosis of porphyria over DEB.[1,2] Differentiation of CEP from hepatoerythropoietic porphyria (HEP), familial form of porphyria cutanea tarda (PCT), harderoporphyria and erythropoietic protoporphyria (EPP), which can present in a similar manner, is based on estimation of different porphyrins in the RBC, urine and stool. Earlier, erythrodontia was considered pathognomic of CEP.[2] Recently, it has been described in HEP, EPP and familial PCT as well.[3] Erythrodontia as an isolated finding too has been described in babies born to CEP mothers. Transplacentally acquired transient porphyria was suggested as the underlying mechanism.[4]

CEP, also known as Gunther's disease, is the most mutilating, fortunately rare, form of porphyria. It is inherited in an autosomal-recessive manner and is caused by deficiency of the enzyme uroporphyrinogen III synthase. CEP usually presents soon after birth with the appearance of red urine, severe photosensitivity (child screams when exposed to sun) and blistering on the sun-exposed parts. Subsequently, patients develop scarring, milia formation, hypertrichosis on the sun exposed parts and cicatrizing alopecia on the scalp. CEP is the most mutilating type and may result in loss of acral tissues, including fingers, and facial mutilation. Erythrodontia of both deciduous and permanent teeth is seen and is considered pathognomic of CEP. Other features seen in CEP include irregular hyperpigmentation and hypopigmentation, growth retardation, ectropion, symblepharon, loss of vision, hemolytic anemia, thrombocytopenia, splenomegaly, porphyrin gallstones and osteopenia. Milder forms of the disease resemble Porphyria cutanea tarda (PCT), and may present in adult life. The diagnosis is suspected clinically when the baby presents with severe photosensitivity, vesicobullous eruptions and red urine. Laboratory confirmation requires demonstration of elevated uroporphyrin and coproporphyrin in marrow normoblats (and/or plasma) and urine, elevated coproporphyrin in stool and normal δ-aminolevulinic acid and porphobilinogen in urine. Such a pattern of porphyrins not only establishes the diagnosis of CEP but also differentiates CEP from other porphyrias. Enzyme study and histopathology are rarely needed. Histopathology shows subepidermal bulla with minimal inflammation. There is perivascular deposition of porphyrins, which can be appreciated with a fluorescence microscope. Treatment is essentially preventive and includes strict avoidance of sunlight, surveillance of the anemia and treatment of recurrent skin infections. Oral activated charcoal has been used; it acts by reducing the absorption of endogenous porphyrins. Repeated transfusions of packed cells to maintain the hematocrit level at 33% reduces the demand for heme synthesis and, hence, reduces porphyrin production. However, iron overload is a serious concern. Bone marrow transplantation can be an effective treatment. At times, splenectomy is needed to control hemolytic anemia. Interestingly, it has also resulted in improvement of cutaneous photosensitivity.[1,5,6]