Co-occurrence of Ichthyosis Vulgaris, Dowling-Degos Disease, and Hidradenitis Suppuritiva in Same Patient: An Association or Coincidence?

Sir,

A 42-year-old male presented with the multiple, asymptomatic, progressive hyperpigmented macules and pits over the face, neck, and flexures of the upper and lower limb for 20 years. The lesions were progressive with the appearance of keratotic papules on the face that healed with pitted scars. A family history of similar lesions was present in 3 of 8 members.

He had recurrent, painful nodular swellings in both the axilla with pus-filled discharge since the last 5 years. He also had dryness and scaling on the skin since 4–6 weeks after birth. A personal and family history of atopy was present. His grandfather and brother had similar complaints in the family.

On examination, there were multiple follicular hyperpigmented macules and pits present over the face, neck, upper back, bilateral axillae, cubital and popliteal fossae. Few polyparous comedones were present on the anterior trunk and upper back. Bilateral axillae showed multiple nodules and scars of previously healed nodules. There were brown, fine, thin polygonal scales over the lower trunk, buttocks, and upper thighs suggestive of ichthyosis vulgaris [Figure 1]. Skin biopsy from hyperpigmented macule revealed follicular plugging with filiform projections and branching of the rete ridges arising from the follicular epithelium forming an antler-like pattern with melanization at tips. Dermoscopy of hyperpigmented lesions showed multiple darkly pigmented dots in the background of the light brown area and star-shaped pattern of pits [Figure 2]. Histopathology of scaly lesion dictated orthokeratosis with hypogranulosis, suggestive of ichthyosis vulgaris. Scaly lesions on dermoscopy showed fine and bright white colored scales with free edges in a criss-cross pattern, predominantly in skin creases on the background of hypopigmented and hyperpigmented areas [Figure 3]. Complete blood count with differentials and platelet counts, erythrocyte sedimentation rate were within normal limits

Figure 1.

Clinically, multiple hyperpigmented macules with polyporous comedones present over neck, upper back. Pits are also present . (a,b) Widely apart multiple nodules are present with scarring at some places along with hyperpigmented macules and pits in both axillae (c) Fine, polygonal scales are present diffusely on lower back, buttocks, and thigh (d)

Figure 2.

Skin biopsy from hyperpigmented macule revealed follicular plugging with filiform projections and branching of the rete ridges arising from the follicular epithelium forming an antler-like pattern with melanisation at tips. (a with 10x magnification, H and E staining). Dermoscopy of hyperpigmented lesions showed multiple darkly pigmented dots in the background of the light brown area (b) and star-shaped pattern of pits (c) (Dermlite 3, 10x)

Figure 3.

Histopathology of scaly lesion dictated orthokeratosis with hypogranulosis, suggestive of ichthyosis vulgaris (a with 10x magnification) (H & E stain). Scaly lesions on dermoscopy showed fine and bright white colored scales with free edges. Scales were present in a criss-cross pattern, predominantly in skin creases on the background of hypopigmented and hyperpigmented areas (b). (Dermlite 3, 10x magnification)

The diagnosis of Dowling-Degos disease (DDD), Hidradenitis Suppurativa (HS), and Icthyosis vulgaris (IV) was made based on the clinical picture, dermoscopy and histopathology. He was prescribed 1% clindamycin cream for axilla, emollients and oral isotretinoin (0.5 mg/kg/day) for 6 weeks.

IV is caused by loss-of-function mutations in the filaggrin gene, as a consequence, there is decrease in the size and number, or even a complete absence of epidermal (F-type) keratohyalin granules.[1] DDD is an autosomal dominant disorder that is caused by mutations in genes involved in melanosome trafficking, melanocyte and keratinocyte proliferation, differentiation, and cellular communication. Classic DDD is caused by a loss-of-function mutation in keratin 5 gene (KRT5).[2] Mutations in PSENEN gene have been attributed to a variant of DDD associated with (HS).[3] HS and epidermoid cysts have been described in a variant of DDD.[4] The Notch signaling pathway plays an integral part in skin homeostasis by regulating the proliferation and differentiation of melanocytes and keratinocytes, further mediating their interactions with one another.[3] HS, also called as acne inversa, thought to be follicular structural abnormality leading to secondary inflammatory reactions. Diagnosis is primarily clinical which requires recognition of the morphology with deep-seated nodules, sinus tracts and scars, flexural location with the nature of chronicity and recurrence of the disease process.

Association of DDD and HS can be explained as both belong to the follicular pathology and alteration in the notch signaling pathway. Also, DDD and IV are reported in a case by Saurabh et al.[5] Presentation of the former two diseases with IV may be coincidence or an association. So far, its pathophysiology has not been established yet, but mosaicism may be considered.

This case is reported because of the rare concurrence of these diseases in same patient. They may have an association, which needs to be further investigated.

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