Long-undiagnosed histoid leprosy in a young female

Case report

A 25-year old female presented with an 8-year history of recurrent erythematous, itchy, and raised lesions, with exacerbation over the last three months. She also reported systemic symptoms of episodic fever, weight loss, and recurrent headaches. These episodes recurred annually over several years and resolved spontaneously, or after treatment. She denied any history of nasal stuffiness, discharge, or epistaxis. She had used various oral medications over several years, including antihistamines and topical corticosteroids, prescribed for presumed diagnoses. There was no history of anti-leprotic therapy or systemic immunosuppressive treatment.

Informed patient consent had been obtained.

On examination, erythematous and hyperpigmented papules and plaques ranging from 0.5 × 0.5 cm to 2 × 2 cm over the face, trunk, and limbs, along with multiple discrete hypopigmented to skin-coloured papules, were present over the back and abdomen (Fig. 1A). A few coin-shaped, atrophic scars were noted on the upper and lower limbs. (Fig. 1B) There was no madarosis, evidence of septal collapse, nor diffuse infiltration of the skin; the lesions were discrete papules and plaques on clinically normal intervening skin.

OPEN IN VIEWER

Figure 1.

(A) Back of the patient showing multiple erythematous and hypopigmented papules and plaques distributed diffusely. (B) Atrophic scars and scattered erythematous papules, hyperpigmented plaques present over both the lower extremities, along with xerosis. (C) Skin biopsy showing grenz zone, collection of foamy histiocytes, spindle cells and lymphocytes (haematoxylin and eosin (H&E) 10×). (D) Stain section showing lepra bacilli with bacillary index of 5+ (Wade Fite stain 100×).

Sensory examination revealed 20% loss of touch and temperature below the knees, consistent with a stocking distribution; no glove pattern sensory loss was noted in the upper limbs, without any motor weakness, but thickened and non-tender ulnar, radial cutaneous, common peroneal, and tibial nerves were palpable.

Slit skin smear for bacteriological index (BI) of Mycobacterium leprae showed 5+. Skin biopsy showed a grenz zone, a collection of foamy histiocytes, spindle cells and lymphocytes and the presence of acid-fast bacilli, with a BI of 5+ (Fig. 1C and D).

Multibacillary multidrug anti-leprosy therapy was started, including monthly supervised doses of rifampicin 600 mg and clofazimine 300 mg, and daily self-administered dapsone 100 mg and clofazimine 50 mg.

Discussion

Histoid leprosy was first described by Wade in 1960, ¹ as a rare and distinct variant of lepromatous leprosy. This continues to challenge with its atypical presentations and poses diagnostic conundrums. It typically presents as firm, shiny, skin-coloured to erythematous papules and nodules. While often associated with relapse in patients on dapsone monotherapy, de novo cases have been reported. ² Clinical presentations can vary, including keloid-like lesion ³ and umbilicated papules, nodules with atrophic scarring. ² Lepra reactions in histoid leprosy are not frequent and are mainly Type 2 reactions that have been described with different incidence, with very few case reports of type 1 lepra reaction. ⁴ Most cases are diagnosed earlier due to their visible and symptomatic nature of lesions. ⁵ Our case had mixed morphology, with an absence of keloid-like or umbilicated lesions commonly associated with histoid leprosy, underlining the importance of maintaining a high index of suspicion for leprosy in any chronic, recurrent nodular or papuloplaque skin condition, especially when accompanied by peripheral nerve thickening or sensory loss, even in the absence of classic features.