The Whiplash Rash.

Sir,

A 16-year-old female presented with high grade fever, associated with evening spike, persistent itchy lesions on body, and acute pain in shoulder, knee, and ankle joints for 3 weeks. She was hospitalized to evaluate the cause of her fever and polyarthralgia. Dermatological examination revealed reddish brown and violaceous patches with few scaly or crusted lichenoid papules and plaques widely distributed on the abdomen, back [Figures 1 and 2], and proximal upper extremities. Lesions were intensely pruritic and appeared flagellate or bizarre due to scratching. Hair, nails, and mucous membranes were normal. She was also found to have cervical lymphadenopathy and a moderate grade splenomegaly. Routine investigations were suggestive of anemia, leukocytosis, a raised erythrocyte sedimentation rate (ESR), a deranged hepatic profile and a very high serum ferritin level (>4000μg/l). A detailed fever profile was done to rule out any infectious cause. Her anti-nuclear antibody (ANA) and Rheumatoid arthritis factor (RF) were negative. Histopathological examination [Figure 3] revealed focal vacuolization, multiple discrete necrotic epidermal keratinocytes, and a mixed superficial perivascular dermal infiltrate. Characteristic lichenoid pruritic bizarre rash, clinical, laboratory findings, and histopathology assisted in establishing the diagnosis of Adult Onset Still's Disease (AOSD).

Figure 1

Red brown and violaceous, lichenoid papules and plaques on abdomen

Figure 2

Flagellate lichenoid dermatitis on back

Figure 3

Multiple discrete necrotic epidermal keratinocytes and focal vacuolization (H and E staining, magnification ×10) (magnified view ×40 inner box)

When features of juvenile rheumatoid arthritis (JRA) syndrome appear in adults, it is referred to as AOSD, as coined by Bywaters.[1] It is a systemic inflammatory disorder characterized by high fever, arthralgia, rash, and variable systemic features. Cases of AOSD are diagnosed based on Yamaguchi and Ohta criteria,[2] which include high intermittent fever, arthralgia, typical rash and leukocytosis as the major ones whereas sore throat, lymphadenopathy and/or splenomegaly, liver dysfunction, negative ANA, and RA factor constitute the minor criteria. Five or more criteria including two major ones should be present to make the definitive diagnosis. Serum ferritin levels, as in our case, are much higher in AOSD and hemophagocytic syndrome as compared to other autoimmune or inflammatory disorders. A dermatologist must consider AOSD in a febrile illness with rash if the serum ferritin is >1000μg/l.[3]

Though known for its classic, salmon-pink, evanescent rash, recent literature on AOSD describes more of atypical eruptions; approximately 29–78% cases are commonly referred to as “persistent pruritic eruptions”.[4] They may be urticarial, lichenoid, dermographism-like, dermatomyosistis-like, prurigo pigmentosa-like or lichen amyloidosis-like. Rarely reported are acneiform, eczematoid, peau'd orange-like or vesicopustular eruptions.[1]

In many cases, rash and fever occur for months or even years before joint symptoms develop. Further, the atypical cutaneous features are reported more often than the classic ones. Dermatologists play a pivotal role in the early diagnosis of such cases and their delineation from other causes of flagellate dermatoses. Causes such as Shiitake mushroom poisoning, chemotherapy (Bleomycin or Docetaxel) induced whiplash rash, dermatomyositis and dermatitis artefacta were ruled out on the basis of clinical history and histopathological examination.[5] Persistent linear pigmentation and dermatomyositis-like flagellate eruption as in our case has been associated with poor prognosis and severe clinical outcomes.[6] Hence, such rash in a case of AOSD should alert the clinician for immediate and aggressive systemic management.

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